Air Quality Data Pathfinder - Find Data

Aerosol Index (AI) is a measurement related to AOD and indicates the presence of an increased amount of tiny suspended particles called aerosols in the atmosphere. In general, a lower AI value indicates more clear skies due to a lower concentration of aerosols. The calculation of the Aerosol Index is based on wavelength-dependent changes in Rayleigh scattering in the ultraviolet (UV) spectral range where ozone absorption is very small. The aerosol index is derived from normalized radiances using 2 wavelength pairs at 340 and 378.5 nm. UVAI can be calculated in the presence of clouds so that daily global coverage is possible. This is ideal for tracking the evolution of episodic aerosol plumes from dust outbreaks, volcanic ash, significant fire events, and biomass burning.

Commonly Used Aerosol Index (AI) Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use. 

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. For more information about the differences between NRT and Standard Science Products, please see Near Real-Time versus Standard Products.

Use Aerosol Index (AI) Data

Tutorials

• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
• NASA's Applied Remote Sensing Training (ARSET) 
  • Satellite Remote Sensing of Dust, Fires, Smoke, and Air Quality
  • An Inside Look at How NASA Measures Air Pollution: This training is tailored to those interested in learning how to access and visualize NASA satellite imagery
  • Introduction and Access to Global Air Quality Forecasting Data and Tools: This training focuses on NASA and European Center for Medium-Range Weather Forecasts (ECMWF) global air quality (AQ) forecasting capabilities. Delivered in collaboration with the Copernicus Atmosphere Monitoring Service (CAMS), this training discusses the basics of AQ forecasting and teaches users how to access and interpret global air quality forecasts
• NASA’s Earthdata: Learn How to Subset Ozone Monitoring Instrument (OMI) Data with NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC) Level 2 Data Subsetter

Use Cases and Articles

• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring the Dixie Wildfire (2021). The Dixie Wildfire was the largest single (i.e. non-complex) wildfire in recorded California history
• Retrieving spatial variation of aerosol level over urban mixed land surfaces using Landsat imageries: Degree of air pollution in Dhaka Metropolitan Area
• Variations in the aerosol index and its relationship with meteorological parameters over Pakistan using remote sensing
• Health And Air Quality Applied Sciences Team (HAQAST) Publications

Data Visualizations

 

NASA's Air Quality and Climate Anomaly Viewer

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• HEG: HDF-EOS to GeoTIFF Conversion Tool

Data Access Tools

The NASA Earthdata Cloud Cookbook has tutorials to help access Earth science data in the cloud

• Find data using Earthdata Search
• How do I access data?
• Read Data

Data Customizing Tools

• GES DISC L2 Subsetter: How to Subset Level-2 Data
• Learn How to Subset Ozone Monitoring Instrument (OMI) Data with NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC) Level 2 Data Subsetter
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring the Dixie Wildfire (2021). The Dixie Wildfire was the largest single (i.e. non-complex) wildfire in recorded California history
• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Access repositories and Jupyter Notebooks used in ARSET trainings through GitHub

Earth Observation Data by Sensor

OMI

The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite has a coarser spatial resolution than MODIS and VIIRS, but provides data at individual wavelengths from the ultraviolet (UV) to the visible. This is important because pollutants have different spectral signatures. For example, a wavelength range around 400 nm can be used to detect elevated layers of absorbing aerosols such as biomass burning and desert dust plumes.

Daily data can be accessed and interactively explored using NASA Worldview:

OMI AI

Using an online interactive tool called Giovanni, map visualizations of OMI AI data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• OMI AI

Level 2 data are available 

• Aerosol Index data from Earthdata Search
  • OMI Aerosol Index data

OMPS

OMPS Aerosol Index layer indicates the presence of UV-absorbing particles in the air.

Daily data can be accessed and interactively explored using NASA Worldview:

• OMPS AI

Level 2 data are available in Earthdata Search:

• OMPS AI

TROPOMI

The Tropospheric Monitoring Instrument (TROPOMI) was co-funded by ESA (European Space Agency) and the Netherlands and is the single payload aboard ESA's Sentinel-5P spacecraft. TROPOMI measures solar radiation reflected by and radiated from Earth.

Research quality data from Earthdata Search:

• TROPOMI AI Data

Reanalysis Data

MERRA-2

The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) is the latest version of global atmospheric reanalysis for the satellite era produced by NASA's Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System Model (GEOS) version 5.12.4. The dataset covers the period of 1980 to present with the latency of about 3 weeks after the end of a month.

Using an online interactive tool called Giovanni, map visualizations of MERRA-2 Aerosol Index data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• Dust TOMS UV Aerosol Index
• Sea Salt TOMS UV Aerosol Index

Atmospheric particulate matter (PM) refers to microscopic particles of solid or liquid matter suspended in the air. These inhalable particles range in size from coarse particles like PM₁₀ that have a diameter of 10 micrometers (μm) or less to finer particles, designated PM_2.5 or PM_1.0, that have a diameter of 2.5 μm, 1.0 μm, or less. While microscopic in size, PM can have a big effect on climate, precipitation, and air quality that may in turn impact human health. 

It's important to be aware of the differences between Aerosol Optical Depth (AOD) and PM_2.5. AOD is an optical measurement averaged over an area in a column of air from the top of the atmosphere to the surface and is a unitless measure. PM_2.5 is a measure of the mass of particles in a specific size range within a given volume of air near the surface taken at a specific point in time. The overall differences between AOD and PM_2.5:

• AOD is an optical measurement; PM_2.5 is a mass concentration measurement
• AOD is an integrated column measurement from the top of the atmosphere to the surface; PM_2.5 is a ground measurement
• AOD is an area-averaged measurement; PM_2.5 is a point measurement

Because the two measurements are so different, it may seem that they are not relatable. However, there are several different techniques to estimate surface concentrations of PM_2.5 from AOD measurements. While there is a relationship between AOD and PM_2.5, there are other factors that can affect AOD, like humidity, the vertical distribution of aerosols, and the shape of the particles. For example, an increase in humidity will increase the size of particles and therefore increase the AOD even though the PM_2.5 level will be the same.

Commonly Used Particulate Matter (PM _2.5) Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

Use PM _2.5 Data

Tutorials

• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
• Applied Remote Sensing Training (ARSET)  
  • EPA AirNow Data and Satellite-Based PM_2.5 Data Sets: Provides guidance for using online tools to access U.S. Environmental Protection Agency (EPA) air quality data, gives examples of applications for surface PM_2.5 estimates, and uses online tools to access and view World Health Organization (WHO) surface PM_2.5 estimates
  • Introduction to Satellite Remote Sensing for Air Quality Applications: This introductory webinar series provides a brief overview of some of the fundamentals essential to understanding the remote sensing process, data products, and their use in air quality applications
  • Satellite Remote Sensing of Dust, Fires, Smoke, and Air Quality: This training helps attendees become familiar with available satellite data, products, and tools, and how to apply them to identify, track, and measure an air quality event
  • An Inside Look at How NASA Measures Air Pollution: This training is tailored to those interested in learning how to access and visualize NASA satellite imagery
  • Satellite Derived Annual PM_2.5 Datasets in Support of United Nations Sustainable Development Goals: Covers data access, analyzing long-term trends, and combining PM_2.5 and population datasets to understand long-term exposure
  • Satellite Observations and Tools for Fire Risk, Detection, and Analysis: This six-part, intermediate training provides lectures and case studies focused on the use of Earth observations for operational fire monitoring: pre-, during-, and post-event

Use Cases and Articles

• NASA Data Tracks Veterans’ Exposure to Smoke and Air Pollution
• No Breathing Easy for City Dwellers: Particulates
• An Extra Air Pollution Burden: New research shows that neighborhoods in Washington, D.C., with more people of color are exposed to more air pollution and have higher rates of disease
• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring Los Angeles Port Backlog (Fall 2021): Beginning around October 2021, the Ports of Los Angeles and Long Beach started suffering serious backlogs of ships due a surge in e-commerce because of the COVID-19 pandemic, resulting in many ships anchored in the ports and causing high amounts of pollutants to be released
• Global Air Quality: ​​Exploring 19 years of particulate matter in the air we breathe
• Citizen-Enabled Aerosol Measurements for Satellites (CEAMS): A Network for High-Resolution Measurements of PM_2.5 and AOD
• SEDAC Releases Air Quality Data for Health-Related Applications: Environmental and public health researchers may benefit from ground-level measurements of PM_2.5, nitrogen dioxide (NO₂), and ozone (O₃) concentrations
• User Profile: Abigail Nastan: Nastan develops new ways of partnering with data users to maximize the benefits of NASA Earth science missions
• Emissions, meteorological and climate impacts on PM_2.5 levels in Southern California using a generalized additive model: Historic trends and future estimates
• Emission factors and evolution of SO₂ measured from biomass burning in wildfires and agricultural fires
• Global premature mortality by dust and pollution PM_2.5 estimated from aerosol reanalysis of the modern-era retrospective analysis for research and applications, version 2
• Health And Air Quality Applied Sciences Team (HAQAST) Publications
• Air Quality Citizen Science

Data Visualizations

 

• Earth Information Center’s Explore App: Enables users to compare air quality data between two locations using maps of PM_2.5, carbon monoxide (CO), nitrogen dioxide (NO₂), ozone (O₃), and sulfur dioxide (SO₂)
• ClimateBits: Unhealthy Air

GIS-Ready Tools and Tutorials

• A Look Back: PM_2.5 in 2020
• A Look Back: Ozone and PM in 2020
• EPA AirData: The EPA's ground-based PM and ozone combined Air Quality Index (AQI) can be accessed at AirNow. AirNow International is an international program for AQI, with information provided from partnering organizations
  • AirNow's Fire and Smoke Map
• U.S. EPA OAQPS AirData air quality monitors
• AirNow Air Quality Monitoring Site Data
• NASA GIS Tutorials and How-Tos
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• For more information about NASA resources for GIS users, visit the GIS Data Pathfinder
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data

Data Access Tools

• NASA’s Air Quality and Climate Anomaly Viewer
• NASA’s HAQAST How To Download NASA Data
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data
• NASA supported OpenAQ: OpenAQ is the world’s largest free and open-source platform for ground-level ambient air quality data. 
• Explorer Data Visualizer
• External: 
  • The Environmental Protection Agency’s ground-based PM and Ozone combined Air Quality Index (AQI) can be accessed at AirNow. AirNow International is an international program for AQI, with information provided from partnering organizations
    • AirNow's Fire and Smoke Map
  • ResourceWatch- Air Quality: Fine Particulate Matter (PM2.5) Station Forecasts
  • NOAA's AerosolWatch
  • CDC's National Environmental Public Health Tracking Network
  • EPA's Outdoor Air Quality (ground station)
  • EPA's Environmental Justice Screening and Mapping Tool
  • EPA’s Environmental Health Data Visualization
  • World Bank provides mean exposure to PM_2.5 across the globe
  • World Health Organization offers country and city level PM_2.5 data for download

Data Customizing Tools

• GES DISC L2 Subsetter: How to Subset Level-2 Data
• Learn How to Subset Ozone Monitoring Instrument (OMI) Data with NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC) Level 2 Data Subsetter
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• Access repositories and Jupyter Notebooks used in ARSET trainings through GitHub.
• ARSET’s Jupyter Notebook via GitHub that accesses VIIRS AOD data and converts AOD to PM_2.5
• NASA supported OpenAQ: OpenAQ is the world’s largest free and open-source platform for ground-level ambient air quality data. 
  • OpenAQ Source Code on GitHub
  • OpenAQ API
• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring Los Angeles Port Backlog (Fall 2021): Beginning around October 2021, the Ports of Los Angeles and Long Beach started suffering serious backlogs of ships due a surge in e-commerce because of the COVID-19 pandemic, resulting in many ships anchored in the ports and causing high amounts of pollutants to be released
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST

Model Data

Hazardous Air Quality Ensemble System (HAQES)

Using the Hazardous Air Quality Ensemble System (HAQES), the Air Quality Laboratory at George Mason University developed real-time surface PM_2.5 composition products as one project of the NASA Health Air Quality Applied Science Team (HAQAST). HAQES is a real-time ensemble forecast of hazardous air quality events, such as wildfires, dust storms, and volcanic eruptions. Regional and global models from multiple agencies have been used to create the ensemble, including NASA's Goddard Earth Observing System (GEOS); the Navy Aerosol Analysis and Prediction System (NAAPS) from the Naval Research Laboratory; the Global Ensemble Forecast System Aerosols (GEFS), High-Resolution Rapid Refresh (HRRR); and the NOAA-EPA Atmosphere-Chemistry Coupler-Community Multiscale Air Quality model (NACC-CMAQ).

• HAQES 3-Hourly Ensemble mean surface total PM_2.5 concentration, V1.0 
  • North America
  • North America, county level
  • North America, census level
• HAQES 3-Hourly Ensemble mean surface total PM_2.5 Organic Carbon concentration, V1.0 
  • North America
  • North America, county level
  • North America, census level
• HAQES 3-Hourly Ensemble mean surface total PM_2.5 Black Carbon concentration, V1.0 
  • North America
  • North America, county level
  • North America, census level

GEOS FP

The GEOS Forward Processing (GEOS FP) model and data assimilation system is the NASA Global Modeling and Assimilation Office's (GMAO) state-of-the-science numerical weather prediction (NWP) model that assimilates conventional and satellite-based weather observations, aerosol optical depth, and ozone in near real-time (NRT) in order to have the best initial conditions for the forecasts: 10-day at 00 UTC and 5-day at 12 UTC. GEOS FP forecasts are used to support a wide range of NASA missions and campaigns. Note that forecasts using the GEOS FP are experimental.

• GEOS FP Forecast Datagrams of PM
• GEOS FP Forecast Maps Surface PM_2.5

GEOS-CF

Goddard Earth Observing System (GEOS) GEOS-Composition Forecast (CF) system forecasts trace gas and aerosol fields using constrained meteorology from GEOS and the GEOS-Chem chemical mechanism. This community-developed, global 3D model of atmospheric chemistry is publicly available and offers five-day forecasts. Forecasts from the GEOS-CF system are experimental.

• GEOS-CF Forecast Datagrams of PM_2.5
• Composition Forecast Maps Surface PM_2.5
• Interactive Composition Forecast Mapping Tool-PM_2.5
  • Users may download historical and forecast data in Excel, ASCII, JSON formats

NASA’s Health and Air Quality Applied Sciences Team (HAQAST) external datasets

• Surface PM _2.5, Atmospheric Composition Analysis Group, Washington University in St. Louis
  • Global/Regional Estimates of Surface PM_2.5
  • North America Estimates of Surface PM_2.5
• Historical PM_2.5 across North America, Atmospheric Composition Analysis Group, Washington University in St. Louis
• Surface Area: Estimates the surface area (SA) of ground-level particulate matter by combining Aerosol Optical Depth (AOD) retrievals from the NASA MODIS and MISR instruments with aerosol vertical profile and scattering properties simulated by the GEOS-Chem chemical transport model
• Daily United States estimates of PM_2.5, Colorado State University (2006-2021): Smoke vs Non-smoke PM_2.5; uses satellite data, EPA ground measurements, and GEOS-Chem
  • Spatially interpolated PM_2.5 concentrations for the US for 2021
  • Spatially interpolated PM_2.5 concentrations for the US from 2019-2020
  • Spatially interpolated PM_2.5 concentrations for the US from 2006-2018, version 2

Reanalysis Data

MERRA-2

MERRA-2 is the latest version of global atmospheric reanalysis for the satellite era produced by NASA's Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System Model (GEOS) version 5.12.4. The dataset covers 1980 to present with the latency of about 3 weeks after the end of a month.

Monthly Dust Surface Mass Concentration (PM_2.5) from MERRA-2 can be accessed and interactively explored using NASA Worldview:

• PM_2.5 data from 1980-present

Using an online interactive tool called Giovanni, data products can be visualized as a time-averaged map, an animation, seasonal maps, scatter plots, or a time series, as well as downloaded in .CSV format:

• Monthly and hourly PM_2.5 datasets

MERRA-2 PM_2.5 in GMAO’s visualization and data access website, FLUID:

• MERRA-2 Atmospheric Reanalysis Map of Surface dry PM_2.5
• MERRA-2 PM_2.5 at Country level is available at NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC)

Earthdata GIS Products:

• Global Annual PM_2.5 Grids

MERRA-2 PM_2.5 in Earthdata Search and Google Earth Engine:

• Surface Mass Concentration of SO₄, BC, OC, dust, and sea salt
• Google Earth Engine: MERRA-2 Aerosol Diagnostics 

Very large dust storms lasting hours or days can be observed and tracked using satellite imagery. The most common source of dust globally is the Sahara Desert. Giant dust storms periodically sweep off the coast of West Africa and can be transported as far as Florida and the Caribbean.The amount of dust transported by these storms can be quantified using the Dust Score, which is calculated from data acquired by the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA’s Aqua satellite. The AIRS Dust Score indicates the level of atmospheric aerosols in Earth’s atmosphere over the ocean. Dust is probable when the score is above 380, and higher scores indicate more certainty that dust is present. The numerical scale is a qualitative representation of the presence of dust in the atmosphere, an indication of where large dust storms may form, and the areas that may be affected.

Commonly Used Dust Score Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. For more information about the differences between NRT and Standard Science Products, please see Near Real-Time versus Standard Products.

Use Dust Score Data

Tutorials

• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
• NASA’s Earthdata: A Clearer View of the Haze – Using NASA GES DISC Data Tools to Examine the June 2020 Sahara Dust Event

Use Cases and Articles

• April dust storm surges through China from the Taklimakan Desert
• AIRS observations of the Tonga undersea volcano eruptions in January 2022
• Health And Air Quality Applied Sciences Team (HAQAST) Publications
• Need help understanding how NASA supports the work of health and air quality stakeholders? Visit NASA’s Health and Air Quality Applied Sciences Team (HAQAST). The HAQAST community includes NASA researchers and stakeholders to help them to better use NASA resources for their health and air quality applications by developing review articles and tutorials, and more

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool

Data Access Tools

• AIRS Applications Browse Tool
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data

Data Customizing Tools

• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks
• Learn How to Subset Ozone Monitoring Instrument (OMI) Data with NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC) Level 2 Data Subsetter
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Access repositories and Jupyter Notebooks used in ARSET trainings through GitHub

Earth Observation Data by Sensor

AIRS

The AIRS Dust Score can be visualized using NASA Worldview:

• Dust Score (Day)
• Dust Score (Night)
  Measurement from the AIRS Infrared quality assurance subset; the imagery resolution is 2 km

Create and share layered maps with AIRS data using the AIRS Browse Tool.

Research quality data products can be accessed using Earthdata Search:

• Dust Score data

Near real-time (NRT) MODIS Surface Reflectance data are available through NASA’s Land, Atmosphere Near real-time Capability for EOS (LANCE) within 60 to 125 minutes after a satellite observation:

• NRT AIRS Dust Score Data 

Nitrogen dioxide (NO₂) is a pollutant, the primary sources of which are automobile exhaust, smoke from industry, and the burning of fossil fuels. If breathed in, NO₂ can aggravate respiratory conditions such as asthma. Long-term exposure can lead to the development of asthma and potentially increase susceptibility to respiratory infections. NO₂ reacts with other chemicals in the atmosphere, forming particulate matter and ozone, producing haze and acid rain, and contributing to nitrogen pollution in coastal waters.

Commonly Used Nitrogen Dioxide Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Nitrogen Dioxide Data

Tutorials

• How to Find and Visualize Nitrogen Dioxide Satellite Data: Find research-quality nitrogen dioxide data to assess regional air quality and potential trends in industrial activity
• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
  • Introduction to Satellite NO₂ data: TROPOMI NO₂ data
  • NASA Giovanni Tutorial: Time-Averaged map of NO₂ Tropospheric Column
  • Downloadable PDF of Tutorial
• NASA's Applied Remote Sensing Training (ARSET):
  • Read, Map, and Analyze OMI NO₂ and SO₂ Data
  • How NASA Measures Nitrogen Dioxide (NO₂)
  • Introducing TROPOMI - High Resolution NO₂ Observations from Space
  • Trace Gas Air Quality Products from OMI and TROPOMI
  • NASA Trace Gas Products

Use Cases and Articles

• Nitrogen Dioxide and Sulfur Dioxide: A picture diary of air quality in the northeastern regions of India, China, and the United States
• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring the following use cases:
  • 2021 California Wildfire Season: Observations of NO₂ levels during the 2021 California wildfire season provide insights into the spread and impact of the fires, help inform public health and safety measures during wildfires, and aid in the development of more accurate fire models and predictions for future wildfire seasons
  • Los Angeles Port Backlog (Fall 2021): Beginning around October 2021, the Ports of Los Angeles and Long Beach started suffering serious backlogs of ships due a surge in e-commerce because of the COVID-19 pandemic, resulting in many ships anchored in the ports that caused high amounts of pollutants to be released
• Augmenting the Standard Operating Procedures of Health and Air Quality Stakeholders With NASA Resources
• NASA's Socioeconomic Data and Applications Center (SEDAC) Releases Air Quality Data for Health-Related Applications
• VOC and trace gas measurements and ozone chemistry over the Chesapeake Bay during OWLETS-2, 2018
• User Profile: Dr. Emily Fischer: Dr. Fischer explores how pollutants move in the lower atmosphere
• Health And Air Quality Applied Sciences Team (HAQAST) Publications
• Need help understanding how NASA supports the work of health and air quality stakeholders? Visit HAQAST. The HAQAST community includes NASA researchers and stakeholders to help them to better use NASA resources for their Health and Air Quality applications by developing review articles and tutorials, and more

Data Visualizations

• Earth Information Center’s Explore App: Enables users to compare air quality data between two locations using maps of PM_2.5, carbon monoxide, nitrogen dioxide, ozone, and sulfur dioxide
• NASA's Visualization, Exploration, and Data Analysis (VEDA) Dashboard: This dashboard explores key indicators to track and compare changes over time
  • Nitrogen Dioxide: Since the outbreak of the novel coronavirus, atmospheric concentrations of nitrogen dioxide have changed by as much as 60% in some regions
• Nitrogen Dioxide Over the United States, 2005-2022
• NASA Studies How COVID-19 Shutdowns Affect Emissions
• Tropospheric Nitrogen Dioxide
• A Tale of Three Cities: Beijing, Los Angeles, Atlanta

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• Exploring NASA's Air Quality resources for GIS
• Air Quality and Climate Anomaly Viewer
• Tropospheric Nitrogen Dioxide (NO₂) Column Density (TROPOMI) in California in Response to the COVID-19 Pandemic
• External:
  • U.S. Environmental Protection Agency (EPA) AirData Monitors

Data Access Tools

• NASA’s Air Quality and Climate Anomaly Viewer
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data
• External:
  • AirNow Air Quality Monitoring Site Data
  • EPA's AirData Monitors
  • EPA's Outdoor Air Quality (ground station)

Data Customizing Tools

• Wisconsin Horizontal Interpolation Program for Satellites (WHIPS) is an open-source program designed to make satellite-derived air quality data more usable. WHIPS interpolates Level 2 satellite retrievals onto a user-defined fixed grid, in effect creating a custom-gridded Level 3 satellite product for the following products: TROPOMI NO₂ and SO₂, OMI NO₂ (NASA and KNMI retrievals), OMI HCHO (NASA and QA4ECV retrievals), OMI SO₂ (NASA retrieval), MOPITT CO (NASA retrieval), MODIS AOD (NASA retrieval)
• OMI and TROPOMI data can be read, processed, and compared using the HARP toolkit, which features command line tools, C library, and interfaces to Python, R, IDL, and MATLAB
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page.

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• earthaccess is a Python library to search, download, or stream NASA Earth science data with just a few lines of code
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• Applied Remote Sensing Training (ARSET)    
  • Introduction to Python Tools for Visualization and Analysis
  •  Python Tools for Analyzing NO₂ Data
• VEDA Dashboard: Since the outbreak of the novel coronavirus, atmospheric concentrations of nitrogen dioxide have changed by as much as 60% in some regions
  • Static view in VEDA documentation
    • View example notebook
  • Interactive session in VEDA 2i2c JupyterHub (requires account)
    • Run example notebook
• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring the following use cases:
  • 2021 California Wildfire Season: Observations of NO₂ levels during the 2021 California wildfire season provide insights into the spread and impact of the fires, help inform public health and safety measures during wildfires, and aid in the development of more accurate fire models and predictions for future wildfire seasons
  • Los Angeles Port Backlog (Fall 2021): Beginning around October 2021, the Ports of Los Angeles and Long Beach started suffering serious backlogs of ships due a surge in e-commerce because of the COVID-19 pandemic, resulting in many ships anchored in the ports that caused high amounts of pollutants to be released
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 

Earth Observation Data by Sensor:

OMI

The Ozone Monitoring Instrument (OMI) aboard NASA’s Aura satellite uses an imaging spectrometer to distinguish between aerosol types, such as smoke, dust, and sulfates. It measures cloud pressure and coverage, which provides data to derive tropospheric ozone. OMI provides a record of total ozone and other atmospheric parameters related to ozone chemistry and climate. OMI also measures pollutants such as ozone, nitrogen dioxide, sulfur dioxide, and aerosols, which the U.S. Environmental Protection Agency (EPA) has designated as posing serious threats to human health and agricultural productivity. 

Daily OMI NO₂ data can be accessed and interactively explored using NASA Worldview:

• OMI NO₂ data

NASA's Air Quality site provides more information on NO₂, as well as trend maps and pre-made images of NO₂ over cities and power plants.

Using an online interactive tool called Giovanni, map visualizations of OMI NO₂ data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• OMI NO₂ Tropospheric Column (30% Cloud Screened) data

Research quality data products can be accessed using Earthdata Search:

• OMI NO₂ Total and Tropospheric Column data

TROPOMI

The Tropospheric Monitoring Instrument (TROPOMI) was co-funded by ESA (European Space Agency) and the Netherlands. It is the single payload aboard ESA's Sentinel-5P spacecraft and measures the solar radiation reflected by and radiated from Earth.

Research quality data:

• TROPOMI NO₂ Data from Earthdata Search
• ESA TROPOMI NO₂ provides additional information about this Level 2 data product

Model Data:

GEOS-CF

Goddard Earth Observing System (GEOS) GEOS-Composition Forecast (CF) system forecasts trace gas and aerosol fields using constrained meteorology from GEOS and the GEOS-Chem chemical mechanism. This community-developed, global 3D model of atmospheric chemistry is publicly available and offers five-day forecasts. Forecasts using the GEOS system are experimental and the use of these forecasts for purposes other than research is not recommended.

• Interactive Composition Forecast Map of NO₂
• Composition Forecast Datagrams of NO₂
• Composition Forecast Maps Surface NO₂

Land Use Regression (LUR)

The Nitrogen Dioxide Surface-Level Annual Average Concentrations Product contains estimated global NO₂ surface values derived using a Land Use Regression (LUR) model (based on 5,220 NO₂ monitors in 58 countries and land use variables) for the years 2010-2012. NO₂ column densities from the Ozone Monitoring Instrument and MERRA-2 scale the concentrations to other years between 1990 and 2020. This product is part of NASA's Health and Air Quality Applied Sciences Team (HAQAST) effort.

Research quality data products can be accessed using Earthdata Search:

• Nitrogen Dioxide Surface-Level Annual Average Concentrations V1

NASA’s Health and Air Quality Applied Sciences Team (HAQAST) external datasets

• Surface NO₂: Global, Atmospheric Composition Analysis Group, Washington University in St. Louis
  • Estimates of annual ground-level nitrogen dioxide (NO₂) concentrations for 2019 with ~1 km resolution created by combining satellite NO₂ column observations from TROPOMI with information from the GEOS-Chem chemical transport model and ground-based monitoring

Field Campaign Observation Data

ATom

The Atmospheric Tomography Mission (ATom) is a NASA Earth Venture Suborbital-2 mission to study the impact of human-produced air pollution on greenhouse gases and on chemically reactive gases in the atmosphere. ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2 to 12 km altitude. Around-the-world flights were conducted in each of four seasons between 2016 and 2018.

• Find Aerosol ATom datasets in Earthdata Search
• Browse ATom datasets at Oak Ridge National Laboratory Distributed Active Archive Center 

The primary sources of sulfur dioxide (SO₂) are the burning of fossil fuels by power plants and industry. Volcanic emissions also contribute SO₂, but in relatively smaller quantities. As with NO₂, SO₂ can aggravate respiratory conditions, especially asthma. In areas with high levels of SO₂, sulfur oxides can react with other components to create small particles that contribute to overall particulate matter. This small particulate matter can contribute to low visibility in areas where SO₂ is high. SO₂ also can lead to acid rain.

Commonly Used Sulfur Dioxide Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Sulfur Dioxide Data

Tutorials

• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
• NASA's Applied Remote Sensing Training (ARSET):    
  • NASA Trace Gas Products
  • Read, Map, and Analyze OMI NO₂ and SO₂ Data
  • Data Analysis Tools for High Resolution Air Quality

Use Cases and Articles

• Monitoring Volcanic Sulfur Dioxide Emissions: NASA monitors volcanic emissions and its impact on global air quality
• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring Los Angeles Port Backlog (Fall 2021): Beginning around October 2021, the Ports of Los Angeles and Long Beach started suffering serious backlogs of ships due a surge in e-commerce because of the COVID-19 pandemic, resulting in many ships anchored in the ports that caused high amounts of pollutants to be released
• Nitrogen Dioxide and Sulfur Dioxide: A picture diary of air quality in the northeastern regions of India, China, and the United States
• Health And Air Quality Applied Sciences Team (HAQAST) Publications

Data Visualizations

• Earth Information Center’s Explore App: Enables users to compare air quality data between two locations using maps of PM_2.5, Carbon Monoxide, Nitrogen Dioxide, Ozone, and Sulfur Dioxide
• VEDA Dashboard: NASA OMI/Aura Sulfur Dioxide (SO₂) Total Column
• AIRS Browse Tool
• Tracking Volcanic Ash With Satellites
• A Tale of Three Cities: Beijing, Los Angeles, Atlanta

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• NASA’s Disaster’s Global Sulfur Dioxide Monitoring Home Page’s Sulfur Dioxide (SO₂) Catalog
• Exploring NASA's Air Quality resources for GIS
• Air Quality and Climate Anomaly Viewer
• External:
  • U.S. Environmental Protection Agency (EPA) AirData Monitors

Data Access Tools

• NASA’s Air Quality and Climate Anomaly Viewer
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data
• External:
  • AirNow Air Quality Monitoring Site Data
  • EPA's AirData Monitors
  • EPA's Outdoor Air Quality (ground station)
  • Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL

Data Customizing Tools

• Wisconsin Horizontal Interpolation Program for Satellites (WHIPS) is an open-source program designed to make satellite-derived air quality data more usable. WHIPS interpolates Level 2 satellite retrievals onto a user-defined fixed grid, in effect creating a custom-gridded level 3 satellite product for the following products: TROPOMI NO₂ and SO₂, OMI NO₂ (NASA and KNMI retrievals), OMI HCHO (NASA and QA4ECV retrievals), OMI SO₂ (NASA retrieval), MOPITT CO (NASA retrieval), MODIS AOD (NASA retrieval)
• OMI and TROPOMI data can be read, processed, and compared using the HARP toolkit which features command line tools, C library, and interfaces to Python, R, IDL, and MATLAB
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring Los Angeles Port Backlog (Fall 2021): Beginning around October 2021, the Ports of Los Angeles and Long Beach started suffering serious backlogs of ships due a surge in e-commerce because of the COVID-19 pandemic, resulting in many ships anchored in the ports that caused high amounts of pollutants to be released
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 

Earth Observation Data by Sensor:

AIRS

The Atmospheric Infrared Sounder (AIRS) is a hyperspectral sounder that collects daily global measurements of water vapor and temperature profiles as one of four instruments comprising the AIRS Project Instrument Suite. When launched in 2002, the AIRS Project Instrument Suite was the most advanced atmospheric sounding system ever deployed in space. AIRS data are combined with data from the Advanced Microwave Sounding Unit (AMSU-A1 and AMSU-A2) and the Humidity Sounder for Brazil (HBS) to provide 3D measurements of temperature and water vapor through the atmospheric column along with measurements of atmospheric trace gases and surface and cloud properties. These data are used by weather prediction centers to improve forecasts and to validate climate models. They also are used in applications ranging from volcanic plume detection to drought forecasting.

NRT AIRS SO₂ data can be accessed and interactively explored using NASA Worldview:

• AIRS SO₂ data

Create and share layered maps with AIRS data using the AIRS Browse Tool.

Research quality data products can be accessed using Earthdata Search:

• AIRS SO₂ (NRT) data

OMI

The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite uses an imaging spectrometer to distinguish between aerosol types, such as smoke, dust, and sulfates. It measures cloud pressure and coverage, which provides data to derive tropospheric ozone. OMI provides a record of total ozone and other atmospheric parameters related to ozone chemistry and climate. OMI also measures criteria pollutants such as ozone, nitrogen dioxide, sulfur dioxide, and aerosols, which the U.S. Environmental Protection Agency (EPA) has designated as posing serious threats to human health and agricultural productivity. 

NRT data can be accessed and interactively explored using NASA Worldview:

• OMI SO₂ data

NASA Global Sulfur Dioxide Monitoring program that provides imagery of daily SO₂ from OMI, OMPS, and TROPOMI. The site also provides information on the source of emissions. 

In addition, the Historical Anthropogenic Sulfur Dioxide Emissions dataset, available through NASA's Socioeconomic Data and Applications Center (SEDAC), offers annual estimates of anthropogenic global and regional SO₂ emissions spanning the period 1850-2005.

Using an online interactive tool called Giovanni, map visualizations of OMI SO₂ data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• OMI SO₂ data

Research quality data products can be accessed using Earthdata Search:

• OMI SO₂ data
  OMI provides daily total column data at a resolution of 13x24 km; data are in HDF5 format

OMPS

The Ozone Mapping and Profiler Suite (OMPS) aboard the joint NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite tracks the health of Earth's ozone layer and measures the concentration of atmospheric ozone. 

Daily data can be accessed and interactively explored using NASA Worldview:

• OMPS SO₂ data

Research quality data products can be accessed using Earthdata Search:

• OMPS SO₂ data

TROPOMI

The Tropospheric Monitoring Instrument (TROPOMI) was co-funded by ESA (European Space Agency) and the Netherlands, and is a space-borne, nadir-viewing, imaging spectrometer covering wavelength bands between the ultraviolet and the shortwave infrared. TROPOMI is the single payload aboard ESA's Sentinel-5P spacecraft and measures the solar radiation reflected by and radiated from Earth.

Research quality data products can be accessed using Earthdata Search:

• TROPOMI SO₂ data
• ESA TROPOMI SO₂ provides additional information about this Level 2 data product

MLS

The Microwave Limb Sounder (MLS) is a passive microwave radiometer/spectrometer that measures microwave thermal emission from the limb (edge) of Earth’s atmosphere to sense vertical profiles of atmospheric gases, temperature, pressure, and cloud ice. MLS measurements are acquired globally day and night and can be obtained in the presence of ice clouds and aerosols that prevent measurements by shorter-wavelength infrared, visible, and ultraviolet sensing techniques. MLS data support investigations in three general scientific areas: stratospheric ozone layer stability, climate change, and air quality. 

MLS NRT data are typically available within three hours of observation and are broken into files containing about 15 minutes of data. The most recent seven days of data are available online.

Research quality data products can be accessed using Earthdata Search:

• MLS SO₂ Data 

Analysis Data

GEOS FP

The GEOS Forward Processing (GEOS FP) model and data assimilation system is GMAO’s state-of-the-science numerical weather prediction (NWP) model that assimilates conventional and satellite-based weather observations, aerosol optical depth, and ozone in near real-time (NRT) in order to have the best initial conditions for the forecasts: 10-day at 00 UTC and 5-day at 12 UTC. GEOS FP forecasts are used to support a wide range of NASA missions and campaigns.

• GEOS FP Forecast: SO₂ Surface Mass Map 
• GEOS FP Forecast: SO₂ Column Mass Map 

Model Data

GEOS-CF

Goddard Earth Observing System (GEOS) GEOS-Composition Forecast (CF) system forecasts trace gas and aerosol fields using constrained meteorology from GEOS and the GEOS-Chem chemical mechanism. This community-developed, global 3D model of atmospheric chemistry is publicly available and offers five-day forecasts. Forecasts using the GEOS system are experimental and use of these forecasts for purposes other than research is not recommended.

• GEOS-CF Forecast Datagrams of SO₂
• GEOS-CF Forecast Maps Surface SO₂

Reanalysis Data

MERRA-2

Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) is the latest version of global atmospheric reanalysis for the satellite era produced by NASA's Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System Model (GEOS) version 5.12.4. The dataset covers the period of 1980-present with the latency of about 3 weeks after the end of a month.

Monthly modeled data from MERRA-2 can be accessed and interactively explored using NASA Worldview: 

• Monthly SO₂ MERRA-2 data 

Global Modeling and Assimilation Office’s offers visualizations of MERRA-2 SO₂ data:

• Interactive MERRA-2 Surface Sulfur Dioxide map 
• Interactive MERRA-2 Sulfur Dioxide Column Mass map

Using an online interactive tool called Giovanni, map visualizations of MERRA-2 SO₂ data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• MERRA-2 SO₂

Field Campaign Observation Data

ATom

The Atmospheric Tomography Mission (ATom) is a NASA Earth Venture Suborbital-2 mission to study the impact of human-produced air pollution on greenhouse gases and on chemically reactive gases in the atmosphere. ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2 to 12 km altitude. Around-the-world flights were conducted in each of four seasons between 2016 and 2018.

• Find Aerosol ATom datasets in Earthdata Search
• Browse ATom datasets at Oak Ridge National Laboratory Distributed Active Archive Center 

Carbon monoxide (CO) is released when something is burned, such as in the combustion of fossil fuels or biomass. Outdoor levels are rarely high enough to cause issues; when they do reach dangerous levels, however, they can affect people with certain types of heart disease. CO is an excellent tracer of pollution transport since it is a long-lived in the atmosphere. It is also helpful for  identifying the source of air masses. 

Commonly Used Carbon Monoxide Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Carbon Monoxide Data

Tutorials

• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
• NASA's Applied Remote Sensing Training (ARSET): 
  • NASA Trace Gas Products
  • Global Air Quality Forecasting by Copernicus 

Use Cases and Articles

• Augmenting the Standard Operating Procedures of Health and Air Quality Stakeholders With NASA Resources
• Communicating respiratory health risk among children using a global air quality index
• NASA’s Air Quality Analytics Collaborative Framework (AQACF) Open-Source API Demonstration Jupyter Notebook featuring the Dixie Wildfire: The Dixie Wildfire was the largest single (i.e. non-complex) wildfire in recorded California history
• Carbon Monoxide from California Wildfires Observed by NASA
• NASA Tracks Carbon Monoxide from the 2020 Australia Fires
• Health And Air Quality Applied Sciences Team (HAQAST) Publications
• Need help understanding how NASA supports the work of health and air quality stakeholders? Visit NASA’s Health and Air Quality Applied Sciences Team (HAQAST). The HAQAST community includes NASA researchers and stakeholders to help them to better use NASA resources for their Health and Air Quality applications by developing review articles and tutorials, and more

Data Visualizations

• Earth Information Center’s Explore App: Enables users to compare air quality data between two locations using maps of PM_2.5, Carbon Monoxide, Nitrogen Dioxide, Ozone, and Sulfur Dioxide.
• MOPITT Product Visualization
• GeoCarb Observes Greenhouse Gasses from Geosynchronous Orbit
• Carbon Emissions from Fires: 2003-2018
• Simulated Surface Carbon Monoxide

GIS-Ready Tools and Tutorials

• Air Quality and Climate Anomaly Viewer
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• For more information about NASA resources for GIS users, visit the GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• External:
  • U.S. Environmental Protection Agency (EPA) AirData Monitors

Data Access Tools

• MOPITT Search and Subsetting Web Application
• MOPITT Product Visualization
• NASA’s Air Quality and Climate Anomaly Viewer
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data
• External:
  • AirNow Air Quality Monitoring Site Data
  • EPA's Outdoor Air Quality  (ground station)
  • Eruptions, Earthquakes, & Emissions (Smithsonian)
  • Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL

Data Customizing Tools

• MOPITT Search and Subsetting Web Application
• Wisconsin Horizontal Interpolation Program for Satellites (WHIPS) is an open-source program designed to make satellite-derived air quality data more usable. WHIPS interpolates level 2 satellite retrievals onto a user-defined fixed grid, in effect creating a custom-gridded Level 3 satellite product for the following products: TROPOMI NO₂ and SO₂, OMI NO₂ (NASA and KNMI retrievals), OMI HCHO (NASA and QA4ECV retrievals), OMI SO₂ (NASA retrieval), MOPITT CO (NASA retrieval), MODIS AOD (NASA retrieval)
• OMI and TROPOMI data can be read, processed, and compared using the HARP toolkit which features command line tools, C library, and interfaces to Python, R, IDL, and MATLAB
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 

Earth Observation Data by Sensor

AIRS

NASA’s Atmospheric Infrared Sounder (AIRS), in conjunction with the Advanced Microwave Sounding Unit (AMSU), senses emitted infrared and microwave radiation from Earth to provide a 3D look at Earth's weather and climate. Working in tandem, the two instruments make simultaneous observations of Earth's surface. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3D map of atmospheric temperature and humidity, cloud amounts and heights, greenhouse gas concentrations and many other atmospheric phenomena. Launched into Earth orbit in 2002, the AIRS and AMSU instruments are aboard NASA's Aqua spacecraft and are managed by NASA's Jet Propulsion Laboratory in Southern California.

NRT and daily data can be accessed and interactively explored using NASA Worldview:

• AIRS CO data
  AIRS Level 2 data are nominally 45 km/pixel at the equator but the data in Worldview have been resampled into a 32 km/pixel visualization. The data are in units of parts per billion by volume at the 500 hPa pressure level, which is approximately 5,500 meters (18,000 feet) above sea level

Create and share layered maps with AIRS data using the AIRS Browse Tool.

Research quality data products can be accessed using Earthdata Search:

• AIRS CO data
  The Atmospheric Infrared Sounder (AIRS) measures abundances of trace components in the atmosphere, including CO. Data are available daily (AIRS3STD), over 8 days (AIRS3ST8), or monthly (AIRS3STM). The instrument measures the amount of CO in the total vertical column profile of the atmosphere (from Earth’s surface to top-of-atmosphere)

MLS

The Microwave Limb Sounder (MLS) instrument aboard NASA's Aura satellite collects Carbon Monoxide (CO) Mixing Ratio layer at 215 hectopascals (hPa). This indicates carbon monoxide levels at the vertical atmospheric pressure level of 215 hPa and is measured in parts per billion by volume (ppbv). 

Daily data can be accessed and interactively explored using NASA Worldview:

• MLS CO data: Visualization of the amount of Carbon Monoxide (215 hPa, Day and Night) (measured in ppbv) 

Near real-time (NRT) data are typically available within 3 hours of observation and are broken into files containing about 15 minutes of data. The most recent 7 days of data are available online. Spatial coverage is near-global (-82º to +82º latitude) with each profile spaced 1.5º or ~165 km along the orbit track (roughly 15 orbits per day). The vertical coverage is from 215 to 0.1 hPa.

Research quality (Level 2) data are available through Earthdata Search:

• MLS/Aura Near-Real-Time L2 Carbon Monoxide (CO) Mixing Ratio NRT
  • This product contains CO profiles derived from the 240 GHz region

MOPITT

The Measurement of Pollution in the Troposphere (MOPITT) instrument aboard NASA's Terra satellite is designed to enhance our knowledge of the lower atmosphere and to observe how it interacts with the land and ocean biospheres. MOPITT’s specific focus is on the distribution, transport, sources, and sinks of carbon monoxide in the troposphere.

Daily and monthly data can be accessed using NASA Worldview:

• MOPITT CO data

Using an online interactive tool called Giovanni, data products can be visualized as a time-averaged map, an animation, seasonal maps, scatter plots, or a time series, as well as downloaded in .CSV format:

• MOPITT CO data (Monthly) (Note: At time of publication, these data are only available through May 2022.)

Research quality data products can be accessed using Earthdata Search:

• MOPITT CO data
  The Measurements of Pollution in the Troposphere (MOPITT) instrument measures the amount of CO present in the total vertical column of the lower atmosphere (troposphere) and is measured in mole per square centimeter (mol/cm2); data are available daily or monthly, and are acquired using the thermal and near-infrared channels

TROPOMI

The Tropospheric Monitoring Instrument (TROPOMI) was co-funded by ESA (European Space Agency) and the Netherlands, and is a space-borne, nadir-viewing, imaging spectrometer covering wavelength bands between the ultraviolet and the shortwave infrared. TROPOMI is the single payload aboard ESA's Sentinel-5P spacecraft and measures the solar radiation reflected by and radiated from Earth. 

Research quality data products can be accessed using Earthdata Search:

• TROPOMI CO data

Model Data

GEOS FP

The GEOS Forward Processing (GEOS FP) model and data assimilation system is GMAO’s state-of-the-science numerical weather prediction (NWP) model that assimilates conventional and satellite-based weather observations, aerosol optical depth, and ozone in near real-time (NRT) in order to have the best initial conditions for the forecasts: 10-day at 00 UTC and 5-day at 12 UTC. GEOS FP forecasts are used to support a wide range of NASA missions and campaigns. There is no data assimilation of CO observations in GEOS FP.

• GEOS FP Forecast Datagrams of CO
• GEOS FP Forecast Maps of 3D CO

GEOS-CF

GEOS-Composition Forecast (CF) system forecasts trace gas and aerosol fields using constrained meteorology from GEOS and the GEOS-Chem chemical mechanism. This community-developed, global 3D model of atmospheric chemistry is publicly available and offers 5-day forecasts. Forecasts using the GEOS system are experimental and are produced for research purposes only. There is no data assimilation of CO observations in GEOS-CF. 

• GEOS-CF Forecast Datagrams of CO
• GEOS-CF Forecast Maps Surface CO
• GEOS-CF  Forecast Maps of Total Column CO

Field Campaign Observation Data

ATom

The Atmospheric Tomography Mission (ATom) is a NASA Earth Venture Suborbital-2 mission to study the impact of human-produced air pollution on greenhouse gases and on chemically reactive gases in the atmosphere. ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2 to 12 km altitude. Around-the-world flights were conducted in each of four seasons between 2016 and 2018.

• Find Aerosol ATom datasets in Earthdata Search
• Browse ATom datasets at Oak Ridge National Laboratory Distributed Active Archive Center 

Ozone (O₃) is a trace gas that can be either beneficial or harmful depending on where it is found in the atmosphere. Beneficial O₃ is found naturally in trace amounts in the upper atmosphere (the stratosphere) where it protects life on Earth from the Sun’s ultraviolet (UV) radiation. Harmful O₃ is found in the troposphere, the lowest layer of the atmosphere, where it serves as a potent greenhouse gas and can aggravate existing health problems in humans, especially those with respiratory conditions. O₃ is not emitted directly into the atmosphere, but instead forms from the chemical reaction between nitrogen oxides and volatile organic compounds that are emitted from power plants, industrial facilities, and cars powered by internal combustion engines (there are also natural emissions of nitrogen oxides and volatile organic compounds from lightning, soil, and vegetation). Reactions to create O₃ take place in the presence of sunlight. Because of the need for sunlight, unhealthy levels of O₃ are often reached on very sunny days and in urban environments.

Commonly Used Ozone Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Ozone Data

Tutorials

• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
• NASA's Applied Remote Sensing Training (ARSET)
  • Satellite Remote Sensing for Measuring Urban Heat Islands and Constructing Heat Vulnerability Indices

Use Cases and Articles

• Tracking Ozone Pollution in the Great Lakes Region
• Great Air Quality for the Great Lakes Region
• Augmenting the Standard Operating Procedures of Health and Air Quality Stakeholders With NASA Resources
• SEDAC Releases Air Quality Data for Health-Related Applications: Environmental and public health researchers may benefit from ground-level measurements of PM_2.5, NO₂, and O₃ concentrations
• User Profile: Dr. Emily Fischer: Dr. Fischer explores how pollutants move in the lower atmosphere
• Mapping Air Quality Using NASA Earth Observations to Investigate Recent Increases in Ozone Concentrations
• Health And Air Quality Applied Sciences Team (HAQAST) Publications.

Data Visualizations

• Earth Information Center’s Explore App: Enables users to compare air quality data between two locations using maps of PM_2.5, Carbon Monoxide, Nitrogen Dioxide, Ozone, and Sulfur Dioxide
• A Tale of Three Cities: Beijing, Los Angeles, Atlanta
• Ozonewatch 2021
• Reduction in Tropospheric NOx and Ozone Corresponding to Worldwide COVID-19 Lockdowns
• NASA Finds Local Lockdowns Brought Global Ozone Reductions
• NASA Models the Complex Chemistry of Earth's Atmosphere
• The Complex Chemistry of Surface Ozone Depicted in a New GEOS Simulation
• Simulation of Surface Ozone

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• Exploring NASA's Air Quality resources for GIS
• Air Quality and Climate Anomaly Viewer
• External:
  • EPA AirData: The Environmental Protection Agency’s ground-based PM and Ozone combined Air Quality Index (AQI) can be accessed at AirNow. AirNow International is an international program for AQI, with information provided from partnering organizations
  • EPA's AirData Monitors

Data Access Tools

• NASA’s Air Quality and Climate Anomaly Viewer
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data
• External:
  • AirNow Air Quality Monitoring Site Data
  • EPA's Outdoor Air Quality  (ground station)
  • EPA's Environmental Justice Screening and Mapping Tool
  • Eruptions, Earthquakes, & Emissions (Smithsonian)

Data Customizing Tools

• OMI and TROPOMI data can be read, processed, and compared using the HARP toolkit, which features command line tools, C library, and interfaces to Python, R, IDL, and MATLAB
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page.
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks
• Learn How to Subset Ozone Monitoring Instrument (OMI) Data with NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC) Level 2 Data Subsetter

Programming Tools

• Google Earth Engine: Sentinel-5 precursor/TROPOMI Level 2 Product User
• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• earthaccess is a python library to search, download or stream NASA Earth science data with just a few lines of code
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics

Earth Observation Data by Sensor

AIRS

The Atmospheric Infrared Sounder (AIRS) is a hyperspectral sounder that collects daily global measurements of water vapor and temperature profiles as one of four instruments comprising the AIRS Project Instrument Suite. 

Using an online interactive tool called Giovanni, map visualizations of AIRS Ozone data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• AIRS O₃ data (data are daily and monthly)

Research quality data products can be accessed using Earthdata Search:

• AIRS O₃ data
  AIRS measures abundances of trace components in the atmosphere including ozone. Data are available daily (AIRS3STD), over 8 days (AIRS3ST8), or monthly (AIRS3STM). The instrument measures the amount of O₃ in the total vertical column profile of the atmosphere (from Earth’s surface to top-of-atmosphere); data are in HDF format

OMI

The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite has a coarser spatial resolution than MODIS and VIIRS, but provides data at individual wavelengths from the ultraviolet (UV) to the visible. This is important because pollutants have different spectral signatures. For example, a wavelength range around 400 nm can be used to detect elevated layers of absorbing aerosols such as biomass burning and desert dust plumes.

Daily data can be accessed using NASA Worldview:

• OMI O₃ data
  Visualization of the amount of ozone in the total column measured in Dobson Units (DU)

Using an online interactive tool called Giovanni, data products can be visualized as a time-averaged map, an animation, seasonal maps, scatter plots, or a time series, as well as downloaded in .CSV format:

• OMI O₃ data (data are daily)

Research quality data products can be accessed using Earthdata Search:

• OMI O₃ Total Column, 12 x 24 km
• OMI O₃ Total Column Zoomed, 13 x 12km

MLS

Ozone (O₃) in the lower stratosphere and upper troposphere as measured by the Microwave Limb Sounder (MLS) instrument aboard NASA's Aura satellite. The O₃ Mixing Ratio layer at 46 hectopascals (hPa) indicates ozone levels at the vertical atmospheric pressure level of 46 hPa, and is measured in parts per billion by volume (ppbv). It is derived from the MLS Ozone product (ML2O3_NRT) available from the MLS. The sensor resolution is 5 km and imagery resolution is 2 km.

Daily data can be accessed and interactively explored using NASA Worldview:

• MLS O₃ data - Visualization of the amount of ozone in the total column (measured in ppmv/ppbv)

Near real-time (NRT) data are typically available within 3 hours of observation and are broken into files containing about 15 minutes of data. The most recent 7 days of data are available online. Spatial coverage is near-global (82º north and south latitude), with each profile spaced 1.5º or ~165 km along the orbit track (roughly 15 orbits per day). The vertical coverage is from 261 to 0.1 hPa.

Research quality (Level 2) data are available through Earthdata Search:

• MLS/Aura Near-Real-Time L2 Ozone (O₃) Mixing Ratio

TROPOMI/Sentinel-5P

The European Space Agency (ESA) and the Copernicus Sentinel Project make available the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) atmospheric composition data to NASA for access and distribution. Sentinel-5P is the first of the Atmospheric Composition Sentinels and provides measurements of O₃, NO₂, SO₂, CH₄, CO, formaldehyde, aerosols, and cloud at high spatial, temporal, and spectral resolutions.

• TROPOMI Tropospheric Ozone Column data are available in Earthdata Search

OMPS

The OMPS instrumental suite aboard the joint NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP), NOAA-20, and NOAA-21 satellites are now the operational instruments for the NASA and NOAA ozone monitoring program. OMPS consists of three ozone measuring sensors that operate in UV and VIS spectral ranges and sample the same air-masses within a few minutes. The OMPS Nadir Mapper (OMPS-NM) was designed to measure atmospheric total column ozone with configurable nadir temporal (along-track) and spatial (across-track) resolutions. The OMPS-NM aboard Suomi NPP collects data at a larger 50 x 50 km pixel size, while NOAA-20 and NOAA-21 OMPS-NM observations are collected at a smaller pixel size. OMPS-NM also offers SO₂ and other trace gas measurements but lacks spectral coverage in the violet-blue wavelength typically used for NO₂ retrievals. (Note: NO₂ observations are possible from OMPS, but they are less optimal as compared with OMI.) OMPS Limb Profilers (OMPS-LP) aboard the Suomi NPP and NOAA-21 satellites provide measurements of vertical ozone profiles in the stratosphere. Tropospheric ozone column is estimated by combining these measurements with total columns from OMPS-NM and meteorological data. The OMPS tropospheric column record extends tropospheric measurements from the Aura OMI/MLS.

Daily data can be accessed using NASA Worldview:

• OMPS-NPP O₃ data

Research quality (Level 2) data are available through Earthdata Search:

• OMPS-NPP L2 NM Ozone (O₃) Total Column swath orbital V2
• OMPS-NPP L2 NP Ozone (O₃) Vertical Profile 
• OMPS-NPP L2 NP Ozone (O₃) Vertical Profile swath orbital NRT

Model Data:

GEOS FP

The GEOS Forward Processing (GEOS FP) model and data assimilation system is GMAO’s state-of-the-science numerical weather prediction (NWP) model that assimilates conventional and satellite-based weather observations, aerosol optical depth, and ozone in near real-time (NRT) in order to have the best initial conditions for the forecasts: 10-day at 00 UTC and 5-day at 12 UTC. GEOS FP forecasts are used to support a wide range of NASA missions and campaigns.

• GMAO:
  • Total Ozone Atmospheric Composition (2D) Maps

GEOS-CF

GEOS-Composition Forecast (CF) system forecasts trace gas and aerosol fields using constrained meteorology from GEOS and the GEOS-Chem chemical mechanism. This community-developed, global 3D model of atmospheric chemistry is publicly available and offers 5-day forecasts. Forecasts using the GEOS system are experimental.

• GMAO:
  • Interactive Composition Forecast Map of O₃
  • Composition Forecast Maps Surface O₃
  • Composition Forecast Maps Total Column O₃
  • Composition Forecast Datagrams of O₃

Reanalysis Data:

MERRA-2

The Ozone Mixing Ratio data product is the MERRA-2 analyzed ozone at 42 pressure levels, along with important meteorological fields such as temperature, wind components, specific humidity, and geopotential height, which are useful for analysis of ozone. 

Monthly data can be accessed and interactively explored using NASA Worldview:

• Ozone Mixing Ratio at 50 hPa (Monthly)

Using an online interactive tool called Giovanni or through the GMAO FLUID webpage, map visualizations of MERRA-2 Ozone data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• Ozone data
• MERRA-2 Total Column Ozone

MERRA-2 Ozone data are available through Earthdata Search and in Google Earth Engine Data Catalog:

• Ozone Mixing Ratio data, 3 hourly
• MERRA-2 Total Column Ozone in Google Earth Engine

Field Campaign Observation Data

ATom

The Atmospheric Tomography Mission (ATom) is a NASA Earth Venture Suborbital-2 mission to study the impact of human-produced air pollution on greenhouse gases and on chemically reactive gases in the atmosphere. ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2 to 12 km altitude. Around-the-world flights were conducted in each of four seasons between 2016 and 2018.

• Find Aerosol ATom datasets in Earthdata Search
• Browse ATom datasets at Oak Ridge National Laboratory Distributed Active Archive Center 

TOLNet

The Tropospheric Ozone Lidar Network (TOLNet) was established in 2012 to provide high spatio-temporal observations of tropospheric ozone to (1) better understand physical processes driving the ozone budget in various meteorological and environmental conditions, and (2) validate the tropospheric ozone measurements of spaceborne missions. Datasets include profiles of tropospheric ozone number density and mixing ratio at a variety of vertical and temporal resolutions as well as collocated surface measurements.

• Find TOLNet datasets in Earthdata Search
• Browse Interactive quicklooks for TOLNet HDF4-GEOMS files on the TOLNet website
• Get Documentation on the TOLNet API

Other links:

• Introduction to TOLNet StoryMap
• Stratospheric Intrusion Observations with TOLNet StoryMap
• TOLNet Data Format Info

Formaldehyde (CH₂O or HCHO) is a volatile hydrocarbon and a known carcinogenic air pollutant common in smoke. Large concentrations of formaldehyde are found in the presence of biomass burning and industrial sites where it is a byproduct of combustion (there also are biogenic emissions of formaldehyde). Formaldehyde affects human health and also has significant—but little understood—effects on Earth’s atmosphere where it contributes to ozone formation. 

Commonly Used Formaldehyde Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Formaldehyde Data

Tutorials

NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:

• How To Download NASA Data
• Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data

Use Cases and Articles

• A Rising Problem: Tackling Denver's ozone requires looking high and low
• OMPS, TROPOMI Instruments Set to Continue OMI's Long-Term Data Record: Data from the next-generation Instruments will help atmospheric scientists advance air quality measurements and standards
• Formaldehyde (HCHO) As a Hazardous Air Pollutant: Mapping Surface Air Concentrations from Satellite and Inferring Cancer Risks in the United States
• Using Aura OMI data to map cancer risks from formaldehyde
• Health And Air Quality Applied Sciences Team (HAQAST) Publications
• Aura OMI formaldehyde (HCHO) data show significant anthropogenic VOC trends in Asian cities over 2005-2019

Data Visualizations

• Mapping Air Quality Using NASA Earth Observations to Investigate Recent Increases in Ozone Concentrations
• Identifying Trends of Ground-level Ozone Precursors in Southeast Michigan and Northern Ohio
• Supporting "Healthy Air, Healthy Planet" in Texas and Beyond
• Measuring the Atmosphere on ATom's Final Flight Around the World

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool

Data Access Tools

• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data
• External:
  • CDC’s National Environmental Public Health Tracking Network

Data Customizing Tools

• Wisconsin Horizontal Interpolation Program for Satellites (WHIPS) is an open-source program designed to make satellite-derived air quality data more usable. WHIPS interpolates Level 2 satellite retrievals onto a user-defined fixed grid, in effect creating a custom-gridded Level 3 satellite product for the following products: TROPOMI NO₂ and SO₂, OMI NO₂ (NASA and KNMI retrievals), OMI HCHO (NASA and QA4ECV retrievals), OMI SO₂ (NASA retrieval), MOPITT CO (NASA retrieval), MODIS AOD (NASA retrieval)
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the Cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• earthaccess is a python library to search, download or stream NASA Earth science data with just a few lines of code
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 
• Earth Engine Data Catalog: Sentinel-5P NRTI HCHO: Near Real-Time Formaldehyde

Earth Observation Data by Sensor:

OMI

The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite measures the amount of formaldehyde (CH₂O), among other constituents in the atmosphere.

Using an online interactive tool called Giovanni, map visualizations of OMI Formaldehyde data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• OMI Formaldehyde

Research quality (Level 2) data are available from Earthdata Search:

• OMI/Aura Formaldehyde (HCHO) Total Column 

OMPS

The OMPS-NPP L2 NM Formaldehyde (HCHO) Total Column swath orbital product provides formaldehyde measurements from the Ozone Mapping and Profiling Suite (OMPS) Nadir-Mapper (NM) instrument on the Suomi-NPP satellite. 

Research quality (Level 2) data are available through Earthdata Search:

• OMPS-NPP L2 NM Formaldehyde (HCHO) Total Column

TROPOMI/Sentinel-5P

The European Space Agency (ESA) and the Copernicus Sentinel Project make available the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) atmospheric sulfur dioxide and formaldehyde data to NASA for access and distribution. Sentinel-5P is the first of the Atmospheric Composition Sentinels and is expected to provide measurements of ozone, NO₂, SO₂, CH₄, CO, formaldehyde, aerosols and cloud at high spatial, temporal and spectral resolutions.

TROPOMI HCHO data are available in Earthdata Search

• 55P L2 HCHO HiR 2: 2020 to present, 5.5 km x 3.5 km
• 55P L2 HCHO HiR 1: 2019 to 2020, 5.5 km x 3.5 km
• 55P L2 HCHO 1: 2018 to 2019, 7.5 km x 3.5 km

Model Data

GEOS-CF

The Goddard Earth Observing System (GEOS) Composition Forecast (CF) system forecasts trace gas and aerosol fields using constrained meteorology from GEOS and the GEOS-Chem chemical mechanism. This global 3D model of atmospheric chemistry is publicly available and offers five-day forecasts with chemical and meteorological diagnostics on the same temporal and spatial resolution. Forecasts using the GEOS system are experimental.

• GEOS-CF model output can be accessed in several ways, either through direct download from the NASA Center for Climate Simulation (NCCS) Dataportal website or remotely accessing the data using the OpENDAP server. For information on available chemical and meteorological diagnostics see the latest File Specification Document
• GEOS-CF Formaldehyde data are also available on Google Earth Engine Data Catalog

Precipitation, particularly rain, affects air quality as it can remove precursors of air pollution, as well as particulate matter. Rain can also suppress certain emissions, such as dust. Higher precipitation amounts generally result in lower aerosol optical depth (AOD) values.

Commonly Used Precipitation Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Precipitation Data

Tutorials

• NASA's Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
• Applied Remote Sensing Training (ARSET)
  • Applications of GPM IMERG Reanalysis for Assessing Extreme Dry and Wet Periods
  • Introduction to Global Precipitation Measurement (GPM) Data and Applications
• Daymet Tutorials
• IMERG Data Tutorials and IMERG Trainings

Use Cases and Articles

• Using the IMERG Long-term Precipitation Dataset for Applications
• Explore 20 Years of Rain and Snowfall Data from NASA’s Precipitation Missions
• Shedding Light on the Future of Earth's Climate with NASA Data
• How NASA Builds Resilience with Climate Models

Data Visualizations

• AIRS Browse Tool
• IMERG Global Viewer
• GPM Precipitation and Applications Viewer 
• What's in the Air: NASA's Atmospheric Infrared Sounder
• Global Fire Weather Database
• Air Quality and Climate Anomaly Viewer
• PMM Image Gallery
• PMM Video Gallery

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool

Data Access Tools

• Daymet Single Pixel Extraction Tool
• AMSR2 Data Access Tool
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data

Data Customizing Tools

• Spatial and Temporal Subsets of Daymet Data Using the THREDDS NetCDF Subset Service (NCSS) for Grids
• Daymet Single Pixel Data Extraction-Web Services
• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• PMM Precipitation and Applications Publisher API
• DaymetPy: A python library for accessing Daymet surface weather data
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL

Earth Observation Data by Sensor

AIRS

The Atmospheric Infrared Sounder (AIRS) is a grating spectrometer aboard NASA's Aqua satellite. In combination with the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), AIRS constitutes an innovative atmospheric sounding group of visible, infrared, and microwave sensors. 

The AIRS Precipitation Estimate is an estimate of daily precipitation measured in millimeters using cloud-related parameters of cloud-top pressure, fractional cloud cover, and cloud-layer relative humidity. The precipitation algorithm is a regression between these parameters and observed precipitation data. It is an estimate from AIRS using a TOVS-like algorithm and is intended for merging into the precipitation product of the Global Precipitation Climatology Project (GPCP).

Create and share layered maps with AIRS data using the AIRS Browse Tool.

Research-quality data products can be accessed using Earthdata Search:

• AIRS/Aqua L2G Precipitation Estimate

AMSR2

The Advanced Microwave Scanning Radiometer 2 (AMSR2) instrument collects data that indicate the rate at which precipitation is falling on the ocean surface in millimeters per hour (mm/hr). 

Data can be accessed and interactively explored using NASA Worldview:

• AMSR2 Surface Precipitation Rate (offered in Day and Night)

Create and share layered maps with AMSR2 data using the AIRS Browse Tool.

Research-quality data products can be accessed using Earthdata Search:

• AMSR2 Surface Precipitation

Near real-time (NRT) Surface Precipitation products are generated within 3 hours by the Land, Atmosphere Near real-time Capability for EOS (LANCE). The NRT products are generated in HDF-EOS-5 augmented with netCDF-4/CF metadata and are available via HTTPS from LANCE. If data latency is not a primary concern, please use science quality products. Science quality products are an internally consistent, well-calibrated record of Earth's geophysical properties to support science.

• NRT AMSR2 Surface Precipitation Rate in Earthdata Search 

GPM

NASA's Precipitation Measurement Missions (PMM) provide a continuous record of precipitation data through the Tropical Rainfall Measuring Mission (TRMM; operational 1997 to 2015) and the Global Precipitation Measurement mission (GPM; launched in 2014). GPM, the TRMM successor mission, provides more accurate measurements, improved detection of light rain and snow, and extended spatial coverage.

IMERG

Data products from TRMM and GPM are available individually and have been integrated with data from a global constellation of satellites to yield precipitation estimates with improved spatial coverage and temporal resolution. The first integrated product was the TRMM Multi-satellite Precipitation Analysis (TMPA), which has been superseded by the Integrated Multi-satellitE Retrievals for GPM (IMERG). IMERG's multiple runs accommodate different user requirements for accuracy and latency (Early = 4 hours, e.g., for flash flood events; Late = 12 hours, e.g., for crop forecasting; and Final = 3 months, with the incorporation of rain gauge data, for research).

GPM data can be visualized using NASA Worldview:

• IMERG Precipitation Rate
• GPM Precipitation Rate

The Short-term Prediction Research and Transition (SPoRT) project at NASA's Marshall Space Flight Center in Huntsville, AL, is a NASA- and NOAA-funded activity to transition experimental/ quasi-operational satellite observations and research capabilities to the operational weather community to improve short-term weather forecasts on a regional and local scale. SPoRT offers a Near Real-Time Viewer for IMERG data:

• GPM IMERG Early
• GPM IMERG Late
• IMERG - Tropics

Users may access and visualize these data directly through ClimateSERV. Additional datasets include IMERG, Evaporative Stress Index, SMAP Soil Moisture, Rainfall, and NDVI.

Using an online interactive tool called Giovanni, map visualizations of IMERG data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• IMERG Final: Data are available from 2000-present
• GPM: includes all IMERG runs, Early, Late, and Final
• TMPA

NASA Earthdata GIS Products:

• Early IMERG Precipitation Rate Image service
• Early IMERG Precipitation Rate Web Map
• Final IMERG Precipitation Rate Image service
• Final IMERG Precipitation Rate Web Map

Near-real time (NRT) data:

• IMERG Early Run Half-Hourly 
  • The "early run" product at NASA's Global Precipitation Measurement website is generated every half hour with a 6-hour latency from the time of data acquisition

Research-quality data products can be accessed using Earthdata Search:

• TMPA
  Rainfall estimates at 3 hours, 1 day, or NRT and accumulated rainfall at 3 hours and 1 day. Data are available from 1997
• IMERG
  Early, Late, and Final precipitation data on the half-hour or 1-day timeframe. Data are available from 2000

Model Data

CHIRPS-GEFS

SERVIR (a joint initiative of NASA, USAID, and geospatial organizations in Asia, Africa, and Latin America) and the Climate Hazards Group (CHG) at University of California at Santa Barbara have developed an improved rainfall forecast dataset that merges two highly recognized datasets: Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) and the NCEP’s Global Ensemble Forecasting System (GEFS). GEFS is a weather forecast system that provides daily forecasts out to 16 days at 1º X 1º resolution at 6-hour intervals.The combined CHIRPS-GEFS dataset uses the higher spatial resolution of CHIRPS and the advanced forecasting ability of GEFS to provide up to a 16-day forecast updated every five days at a global spatial resolution of 5 km. CHIRPS-GEFS model data are available for analysis and download through the SERVIR Product Catalog. Users may access and visualize these data directly through ClimateSERV. 

Daymet

Another NASA source for precipitation data is Daymet, which can be accessed through NASA's Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC). Daymet is a collection of gridded estimates of daily weather parameters including minimum and maximum temperature, precipitation, vapor pressure, radiation, snow water equivalent, and day length at 1 km resolution over North America, Puerto Rico, and Hawaii. Daymet data are available from 1980 to present (North America and Hawaii) and from 1950 to present (Puerto Rico) and can be retrieved in a variety of ways, including: Earthdata Search; an API available through ORNL DAAC; ORNL DAAC tools; and through the Application for Extracting and Exploring Analysis Ready Samples (AppEEARS) application. Along with daily data, annual Daymet climatologies also are available.

GPCP

The Global Precipitation Climatology Project (GPCP) is the precipitation component of an internationally coordinated set that combines observations and satellite precipitation data. 

Using an online interactive tool called Giovanni, map visualizations of GPCP Precipitation data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• GPCP Precipitation data

LDAS

The Land Data Assimilation System (LDAS) includes a global collection (GLDAS), a North American collection (NLDAS), National Climate Assessment-Land Data Assimilation System (NCA-LDAS), and a Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS). LDAS uses measurements including air temperature, precipitation, soil texture, and topography. GLDAS modeled data are available from January 1948 to present. NLDAS modeled datasets are available from January 1979 to present. FLDAS modeled datasets are available from January 1982 to present.

Data can be accessed and interactively explored using NASA Worldview:

• GLDAS Precipitation Total (data only available through 1947 to 2022)
• NLDAS Precipitation Total

Using an online interactive tool called Giovanni, data products can be visualized as a time-averaged map, an animation, seasonal maps, scatter plots, or a time series, as well as downloaded in .CSV format:

• LDAS Precipitation data
  • FLDAS Rainfall data
  • NLDAS Precipitation data
  • NCA-LDAS Precipitation data
  • GLDAS Precipitation data

Reanalysis Data

MERRA-2

The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) provides data beginning in 1980. Due to the amount of historical data available, MERRA-2 data can be used to look for trends and patterns as well as anomalies. There are several options available: 1-hourly, 3-hourly, 6-hourly, daily, and monthly. These options provide information on precipitation.

Data can be accessed and interactively explored using NASA Worldview:

• MERRA-2 Precipitation data in Worldview

Using an online interactive tool called Giovanni, map visualizations of MERRA-2 Precipitation data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• MERRA-2 Precipitation data

GIS Product using MERRA-2 reanalysis data:

• POWER Monthly Meteorology
• POWER Annual Meteorology
• POWER Climatology Meteorology

Research-quality air surface temperature data products can be accessed using Earthdata Search:

• MERRA-2 Precipitation data in Earthdata Search

The NASA Prediction Of Worldwide Energy Resources (POWER) Data Access Viewer provides MERRA-2 meteorological parameters through a web mapping application with the capability for data subsetting, charting, and visualizing. The data are also available via API as well as via OPeNDAP.

•  POWER provides precipitation data
  • POWER meteorological data

Humidity is a measure of the amount of water vapor present in the atmosphere, which can impact air quality. For example, humidity levels affect the chemical reactions that control the formation of certain pollutants, like ozone. Additionally, in urban areas, humid air can trap pollutants close to the ground keeping them from moving and dissipating.

Commonly Used Humidity Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Humidity Data

Tutorials

• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:
  • How To Download NASA Data
  • Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data
• Access AIRS data from GES DISC via OPeNDAP

Use Cases and Articles

• Quantifying the impacts of PM_2.5 constituents and relative humidity on visibility impairment in a suburban area of eastern Asia using long-term in-situ measurements
• Comparison of ground based indices (API and AQI) with satellite based aerosol products
• Cloudy Skies and Better Clean Air Forecasts
• Air Quality Implications for Pollinator Species
• NASA Armstrong takes Weather Instrumentation to New Heights

Data Visualizations

• AIRS Browse Tool
• What's in the Air: NASA's Atmospheric Infrared Sounder

GIS-Ready Tools and Tutorials

• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos

Data Access Tools

The NASA Earthdata Cloud Cookbook has tutorials to help access Earthdata in the cloud

• Find data using Earthdata Search
• How do I access data?
• Read Data

Data Customizing Tools

• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 

Earth Observation Data by Sensor

AIRS

The Atmospheric Infrared Sounder (AIRS) is a hyperspectral sounder that collects daily global measurements of water vapor and temperature profiles as one of four instruments comprising the AIRS Project Instrument Suite. 

Data can be accessed and interactively explored using NASA Worldview:

• AIRS Surface Relative Humidity

Create and share layered maps with AIRS data using the AIRS Browse Tool.

Using an online interactive tool called Giovanni, map visualizations of AIRS Relative Humidity data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• AIRS Relative Humidity

Research-quality data products can be accessed using Earthdata Search:

• AIRS Relative Humidity in Earthdata Search

Reanalysis Data

MERRA-2

The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) provides data beginning in 1980. Due to the amount of historical data available, MERRA-2 data can be used to look for trends and patterns as well as anomalies. There are several options available: 1-hourly, 3-hourly, 6-hourly, daily, and monthly. These options provide information on precipitation.

Monthly data can be accessed and interactively explored using NASA Worldview:

• MERRA-2 Humidity data

MERRA-2 Weather Maps

• Animate and download weather maps for a variety of meteorological parameters, including humidity

Using an online interactive tool called Giovanni, map visualizations of MERRA-2 Humidity data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• MERRA-2 Humidity

GIS Product using MERRA-2 reanalysis data:

• POWER Annual Meteorology
  • QV10M (Specific Humidity at 10 Meters): The ratio of the mass of water vapor to the total mass of air at 10 meters (kg water/kg total air)
  • QV2M (Specific Humidity at 2 Meters): The ratio of the mass of water vapor to the total mass of air at 2 meters (kg water/kg total air)
  • RH2M (Relative Humidity at 2 Meters): The ratio of actual partial pressure of water vapor to the partial pressure at saturation, expressed in percent

Research-quality data products can be accessed using Earthdata Search:

• MERRA-2 Humidity in Earthdata Search
  • There are several options available: 1-hourly, 3-hourly, 6-hourly. These options provide information on surface specific humidity, specific humidity at 2 m, and relative humidity

The NASA Prediction Of Worldwide Energy Resources (POWER) Data Access Viewer provides MERRA-2 meteorological parameters through a web mapping application with the capability for data subsetting, charting, and visualizing. The data are also available via API, GIS enabled, as well as via OPeNDAP.

•  POWER provides Specific Humidity and Relative Humidity at 2 meters

The POWER Meteorological Data Overview provides additional information.

Currents of air carry pollutants from region to region, country to country, and even continent to continent. As these air currents move, they affect atmospheric chemistry by dispersing pollution, diluting concentrations, and creating less favorable conditions for secondary pollutants to form. Strong air currents help disperse pollution, leading to lower concentrations, while weak air currents can help increase the accumulation of pollution in certain locations. Additionally, wind transports pollutants at a given location depending on wind direction and location of source, leading to an increase or decrease in that pollutant. Aerosols are transported by wind, so higher aerosol concentrations are generally measured downwind from source regions.

Commonly Used Wind Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Wind Data

Tutorials

NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:

• How To Download NASA Data
• Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data

Use Cases and Articles

• Smoke over Athens: The effects of forest fires show up in a multi-satellite view of pollution
• Carbon Control: Radiocarbon and satellite data hint at the future of California emissions

Data Visualizations

AIRS Browse Tool

• How-to Guide

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• How to convert LANCE NRT AMSR2 data to GeoTIFF Format using Python
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool

Data Access Tools

• AMSR2 Data Access Tool
  • How-to Guide
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data

Data Customizing Tools

• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 
• CYGNSS: Generic Data Readers

Earth Observation Data by Sensor

AMSR2

Data, often in near real-time (NRT), can be accessed and interactively explored using NASA Worldview:

• AMSR2 Wind Speed (Day, Night)

Create and share layered maps with AMSR2 data using the AIRS Browse Tool.

Research-quality AMSR2 Wind, Level 2 NRT data are available in Earthdata Search from NASA’s Land, Atmosphere Near real-time Capability for EOS (LANCE) 75 to 140 minutes after a satellite observation.

• NRT AMSR2 Unified L2B Global Swath Ocean Products V1 - Wind Direction, Wind Speed

DDMI

The Delay Doppler Mapping Instrument (DDMI) is the single instrument aboard the eight individual satellites comprising NASA’s Cyclone Global Navigation Satellite System (CYGNSS) constellation. Each DDMI contains both a traditional Global Positioning System (GPS) navigation receiver integrated with a reflections processor. The DDMI aboard each of the eight CYGNSS micro-satellites receives signals broadcast from four orbiting GPS satellites along with the return of the same GPS satellite’s signal reflected from Earth. These signals are used to provide measurements of wind speed over the ocean to better understand and predict tropical cyclones.

Data can be accessed and interactively explored using NASA Worldview:

• DDMI Ocean Surface Wind Speed

Research-quality data products can be accessed using Earthdata Search:

• CYGNSS/DDMI Wind NOAA Level 2 Science Wind Speed 25-km Product Version 1.2
• Other CYGNSS/DDMI Wind Products

Reanalysis Data

MERRA-2

The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) provides data beginning in 1980. Due to the amount of historical data available, MERRA-2 data can be used to look for trends and patterns as well as anomalies. There are several options available: 1-hourly, 3-hourly, 6-hourly, daily, and monthly. These options provide information on precipitation.

Monthly data can be accessed and interactively explored using NASA Worldview:

• MERRA-2 Wind Speed data
• MERRA-2 Monthly Surface Wind Speed

MERRA-2 Weather Analyses Maps

• Animate and download weather maps for a variety of meteorological parameters, including:
  • wind speed
  • wind direction

Using an online interactive tool called Giovanni, map visualizations of MERRA-2 Wind data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• MERRA-2 Surface Wind Speed
• MERRA-2 Wind Direction

GIS Product using MERRA-2 reanalysis data:

• POWER Monthly Meteorology
• POWER Annual Meteorology
• POWER Monthly Wind Speed
• POWER Monthly U, V Wind Components
• POWER Annual U, V Wind Components

Research-quality data products can be accessed using Earthdata Search:

• MERRA-2 Surface Wind Speed
• MERRA-2 Eastern and Northward Wind (wind measurements are in meters per second)

The NASA Prediction Of Worldwide Energy Resources (POWER) Data Access Viewer provides MERRA-2 meteorological parameters through a web mapping application with the capability for data subsetting, charting, and visualizing. The data are also available via API, GIS enabled, as well as via OPeNDAP.

•  POWER provides Wind Direction (at 2, 10, and 50 meters)
  • The POWER Meteorological Data Overview provides additional information 

Surface Air Temperature (SAT) refers to the air temperature generally measured at approximately 6.5 feet (about 2 meters) above the ground or ocean surface. Surface air temperature provides a key indicator of climate change, contributing to the “global surface temperature record”.

Commonly Used Surface Air Temperature Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Surface Air Temperature Data

Tutorials

NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide:

• How To Download NASA Data
• Flowchart of Resources and Data Products for Health and Air Quality Applications with an Emphasis on Satellite Data

Use Cases and Articles

• VOC and trace gas measurements and ozone chemistry over the Chesapeake Bay during OWLETS-2, 2018
• Health And Air Quality Applied Sciences Team (HAQAST) Publications

Data Visualizations

• AIRS Browse Tool
• What's in the Air: NASA's Atmospheric Infrared Sounder

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• GES DISC How-To's: How to access the GES DISC IMERG ArcGIS Image Service using the ArcGIS Enterprise Map Viewer
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• Air Quality and Climate Anomaly Viewer

Data Access Tools

• NASA’s Air Quality and Climate Anomaly Viewer
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data
• External:
  • AirNow Air Quality Monitoring Site Data
  • NOAA Climate Data Online
  • EPA's AirData Monitors

Data Customizing Tools

• For information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks
• Learn How to Subset Ozone Monitoring Instrument (OMI) Data with NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC) Level 2 Data Subsetter

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 

Earth Observation Data by Sensor

AIRS

The Atmospheric Infrared Sounder (AIRS) is a hyperspectral sounder that collects daily global measurements of water vapor and temperature profiles as one of four instruments comprising the AIRS Project Instrument Suite. 

Data can be accessed and interactively explored using NASA Worldview:

• AIRS Surface Air Temperature

Create and share layered maps with AIRS data using the AIRS Browse Tool.

Using an online interactive tool called Giovanni, data products can be visualized as a time-averaged map, an animation, seasonal maps, scatter plots, or a time series, as well as downloaded in .CSV format:

• AIRS Surface Air Temperature

Research-quality air surface temperature data products can be accessed using Earthdata Search:

• AIRS Surface Air Temperature

AIRS NRT data are available from NASA’s Land, Atmosphere Near real-time Capability for EOS (LANCE) 75 to 140 minutes after a satellite observation.

Model Data

Daymet

A NASA source for air temperature modeled data is Daymet. Daymet is a collection of gridded estimates of daily weather parameters including minimum and maximum temperature, precipitation, vapor pressure, radiation, snow water equivalent, and day length at 1 km resolution over North America, Puerto Rico, and Hawaii. Daymet data are available from 1980 to present (North America and Hawaii) and from 1950 to present (Puerto Rico).

Research-quality air surface temperature data products can be accessed using Earthdata Search:

• Daymet Air Temperature in Earthdata Search

LDAS

The Land Data Assimilation System (LDAS) includes a global collection (GLDAS), a North American collection (NLDAS), National Climate Assessment - Land Data Assimilation System (NCA-LDAS), and a Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS). LDAS uses measurements including air temperature, precipitation, soil texture, and topography. GLDAS modeled data are available from January 1948 to present. NLDAS modeled datasets are available from January 1979 to present. FLDAS modeled datasets are available from January 1982 to present.

Monthly data can be visualized using NASA Worldview:

• GLDAS Near Surface Air Temperatures 
• NLDAS Air Temperatures (2 m above ground)

Using an online interactive tool called Giovanni, map visualizations of LDAS data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• GLDAS Near Surface Air Temperatures 
• NLDAS Air Temperatures (2 m above ground)
• NCA-LDAS Air Temperatures
• FLDAS Air Temperatures

Reanalysis Data

MERRA-2

The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) provides data beginning in 1980. Due to the amount of historical data available, MERRA-2 data can be used to look for trends and patterns as well as anomalies. There are several options available: 1-hourly, 3-hourly, 6-hourly. These options provide information on surface skin temperature, air temperature at 2 m, and air temperature at 10 m.

Data can be accessed and interactively explored using NASA Worldview:

• MERRA-2 2-meter Air Temperature

MERRA-2 Weather Maps

• Animate and download weather maps for a variety of meteorological parameters, including air temperature

Using an online interactive tool called Giovanni, map visualizations of MERRA-2 Temperature data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• MERRA-2 Temperature

GIS Product using MERRA-2 reanalysis data:

• POWER Monthly Meteorology
• POWER Annual Meteorology
• POWER Climatology Meteorology

Research-quality air surface temperature data products can be accessed using Earthdata Search:

• MERRA-2 Temperature in Earthdata Search

Topography is the general configuration of the land surface, including its relief and the position of its natural features. Factors including regional topography, prevailing wind speed and direction, amount of natural and human-created aerosols, increased industrial growth and urbanization, and high population density can result in unhealthy levels of air pollution that can affect a region for days and weeks. Topographic data are often in the form of Digital Elevation Models (DEMs) or grids with values representing the height of a cell.

Commonly Used Topography/Elevation Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use.

Use Topography Data

Tutorials

• NASA Earthdata YouTube video: Looking to Fill the Voids? NASADEM is Here!
• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide: How To Download NASA Data
• Explore NASA GEDI Aboveground Biomass Datasets, Services, and Tools at ORNL DAAC
• EarthExplorer Tutorial

Use Cases and Articles

• Haze in the Sichuan Basin
• Washington Health & Air Quality Quantifying Air Quality Parameters and Validating Air Pollution Sources Impacting the Health of Puget Sound Residents Through the Use of NASA and ESA Remote Sensing Data
• Oklahoma Health and Air Quality Mapping Air Quality Using NASA Earth Observations to Investigate Recent Increases in Ozone Concentrations
• In the Fog about Smog: Solving the Smog Puzzle on Earth and from Space
• New in CSDA: High Resolution Digital Elevation Models
• Earth in the Third Dimension: First GEDI Data Available

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• Working with Land Remote Sensing Data in a GIS Environment
• AppEEARS allows users to subset data by defining specific point(s) or area(s) of interest; output data can be downloaded in CSV (point), GeoTIFF (area), or NetCDF4 (area) formats.
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool

Data Access Tools

• EarthExplorer
• LandsatLook 
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data

Data Customizing Tools

• AppEEARS allows users to subset data by defining specific point(s) or area(s) of interest; output data can be downloaded in CSV (point), GeoTIFF (area), or NetCDF4 (area) formats
• MODIS/VIIRS Subsetting Tools Suite
• GEDI Subsetting with Earthdata Search Tutorial
• For more information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data.
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 
• GEDI L3 and L4 Tutorials
• GEDI API
• NASA Earthdata Application Programming Interfaces (APIs)
• Getting Started with the AρρEEARS API: Submitting and Downloading an Area Request (Jupyter Notebook)
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code

Earth Observation Data by Sensor

ASTER

The Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Digital Elevation Model provides a global digital elevation model (DEM) of land areas on Earth at a spatial resolution of 1 arc second (approximately 30 meter horizontal posting at the equator).

DEM data accuracy is typically very sensitive to vegetation cover; however, data from the ASTER instrument tend to perform better over specific landcover types. DEM data can be accessed and interactively explored using NASA Worldview:

• ASTER DEM

Research quality topography data products are available from Earthdata Search:

• ASTER Digital Elevation Model V003

In addition to Earthdata Search, SRTM and ASTER data can be accessed through AppEEARS.

GEDI

The Global Ecosystem Dynamics Investigation (GEDI) Level 3 Land Surface Metrics dataset provides gridded mean canopy height, standard deviation of canopy height, mean ground elevation, standard deviation of ground elevation, and counts of laser footprints per 1 km x 1 km grid cells within 52° north and south latitude. Data are available from April 2019 through 2022. Level 3 gridded products can be used to create digital elevation models, characterize important carbon and water cycling processes, and more. 

Users may download customized subsets (Level 3 and Level 4) of GEDI data using the Spatial Data Access Tool through NASA’s Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC).

GEDI L3 Gridded Land Surface Metrics data can be visualized and interactively explored using NASA Worldview:

• GEDI L3 Gridded Land Surface Metrics dataset 

Research quality data can be accessed using Earthdata Search:

• GEDI L3 Gridded Land Surface Metrics, V2

SRTM

One of the most common topography data sources is the Shuttle Radar Topography Mission (SRTM). SRTM provides a DEM of all land between 60° north and 56° south latitude, which encompasses about 80% of Earth's landmass. 

DEM data can be accessed and interactively explored using NASA Worldview:

• SRTM DEM 

Research quality topography data products are available from Earthdata Search:

• SRTM
  These data were acquired in 2000 and are in raw format (with the ".hgt" file extension), and can be opened in most Geographic Information Systems (GIS), such as ArcGIS or QGIS

In addition to Earthdata Search, SRTM can be accessed through AppEEARS.

Model Data

NASADEM

The NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Digital Elevation Model (DEM) version 1 (NASADEM_HGT) dataset provides global elevation data at 1 arc second spacing. NASADEM extends the legacy of the SRTM by improving the DEM height accuracy and data coverage as well as providing additional SRTM radar-related data products. NASADEM are distributed in 1 degree latitude by 1 degree longitude tiles and consist of all land between 60° N and 56° S latitude. This accounts for about 80% of Earth’s total landmass.  

Research quality topography data products are available from Earthdata Search:

• NASADEM

Commonly Used Soil Moisture Data at a Glance

Descriptions of these measurements will be reviewed in more detail later in this Data Pathfinder. The following sections will help guide you to topic-specific data and resources for accessing, visualizing, preparing/manipulating (e.g. subsetting), and analyzing data. Each observation, model, and reanalysis data has unique characteristics that should be considered when evaluating its use. 

An asterisk (*) next to an entry indicates that near real-time (NRT) data products are available through NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE). While not intended for scientific research, NRT data are good resources for monitoring ongoing or time-critical events. To learn more about the difference between NRT and Standard Science Products, see Near Real Time versus Standard Products.

Use Soil Moisture Data

Tutorials

• NASA’s Health and Air Quality Applied Sciences Team (HAQAST) Guide: How To Download NASA Data
• NASA's Applied Remote Sensing Training (ARSET) 
  • Applications of Remote Sensing to Soil Moisture and Evapotranspiration
  • Water Resource Management Using NASA Earth Science Data
• Learn how to Search, Order, and Customize SMAP Data using Earthdata Search (PDF)
• NASA's Soil Moisture Active Passive (SMAP) Mission Data Products 
• SPoRT Training Module: NASA Land Information System (LIS): Soil Moisture Percentile
  • Background information in training modules: 
    • LIS Primer 
    • LIS Applications

Use Cases and Articles

• Great Air Quality for the Great Lakes
• Modeling Regional Pollution Transport Events During KORUS-AQ: Progress and Challenges in Improving Representation of Land-Atmosphere Feedbacks
• Satellite data can reveal fire susceptibility in peatlands

Data Visualizations

• Southern Africa Drought
• Connect the Drops with NASA Data

GIS-Ready Tools and Tutorials

• GIS Data Pathfinder
• NASA GIS Tutorials and How-Tos
• ArcGIS: How to Add NetCDF Data in ArcGIS
• QGIS: How to Add Data
• HEG: HDF-EOS to GeoTIFF Conversion Tool
• How to Import MERRA Surface Product Data into ArcGIS
• Visualize NSIDC data as WMS layers with ArcGIS and Google Earth
• How to Import SMAP HDF Data Into ArcGIS
• Accessing ORNL DAAC OGC services in popular GIS tools
• How to Import AMSR-E Daily Soil Moisture data into ArcGIS
• Decoding MODIS and VIIRS Quality Science Datasets using the ArcGIS MODIS-VIIRS Python Toolbox

Data Access Tools

• Crop Condition and Soil Moisture Analytics (Crop-CASMA) is a freely available online tool developed by the USDA's National Agricultural Statistics Service, NASA, and George Mason University that provides access to high-resolution data from SMAP (and MODIS) in an easy-to-use format
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the cloud
  • Find data using Earthdata Search
  • How do I access data?
  • Read Data

Data Customizing Tools

• Soil Moisture Visualizer
  • NASA's Oak Ridge National Laboratory DAAC (ORNL DAAC) developed a Soil Moisture Visualizer tool (read about it at Soil Moisture Data Sets Become Fertile Ground for Applications) that integrates a variety of North American soil moisture datasets. For more information on the available datasets and use of the visualizer, view the Soil Moisture Visualizer Guide
• AppEEARS allows users to subset data by defining specific point(s) or area(s) of interest. Output data can be downloaded in CSV (point), GeoTIFF (area), or NetCDF4 (area) formats
• MODIS/VIIRS Subsetting Tools Suite
• For more information on a suite of NASA data tools for searching and ordering, data handling, subsetting and filtering, geolocating, reprojecting, and mapping, as well as visualizing and analyzing data, visit the NASA Earthdata Data Tools Page
• The NASA Earthdata Cloud Cookbook has tutorials to help access Earth data in the Cloud
  • How do I subset data granules?
  • How do I reproject and resample a data file?
  • How do I access data using APIs?
• Panoply: NASA’s Panoply visualization tool plots geo-referenced and other arrays from netCDF, HDF, GRIB, and other datasets. It can be used to help plot data on global or regional maps, allow users to select from multiple map projections, and overlay continent outlines or masks

Programming Tools

• The Earthdata Developer Portal is for application developers who wish to build applications that search, access, and browse EOSDIS-hosted Earth science data
• Need help? If you have specific questions about how to use data, tools, or resources mentioned in this Data Pathfinder, please visit the Earthdata Forum. Here, you can interact with other data users and NASA subject matter experts on a variety of Earth science research and applications topics
• If you have general questions about health and air quality data, research, and applications, visit the Health and Air Quality Community Forum, where you can interact with other data users and experts from NASA HAQAST
• earthaccess is a Python library to search, download or stream NASA Earth science data with just a few lines of code
• Examples on how to access and visualize various NASA HDF/HDF-EOS files using Python (pyhdf/h5py), NCL, MATLAB, and IDL, NCL, MATLAB, and IDL 

Earth Observation Data by Sensor

AMSR-2

The Advanced Microwave Scanning Radiometer (AMSR) for EOS (AMSR-E) instrument and the AMSR-2 instrument provide volumetric soil moisture data. The Advanced Microwave Scanning Radiometer 2 (AMSR2) instrument provides global passive microwave measurements of surface soil moisture. Near real-time (NRT) products available through the Land, Atmosphere Near real-time Capability for EOS (LANCE) are generated within 3 hours of the last observations in the file.

Data can be visualized using NASA Worldview:

• AMSR2 Surface Soil Moisture (offered in Day and Night)

Using an online interactive tool called Giovanni, map visualizations of AMSR-2 data can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• AMSR-2 volumetric soil moisture data

Near-real time data:

• AMSR2 NRT data

Research-quality data products can be accessed using Earthdata Search:

• AMSR2 Surface Soil Moisture data

SMAP

NASA's Soil Moisture Active Passive satellite (SMAP, launched in 2015) measures the moisture in the top 5 cm of soil globally daily and every 2-3 days at a resolution of 9-36 km. 

Near real-time SMAP imagery can be accessed and interactively explored using NASA Worldview:

• SMAP (includes root zone and surface soil moisture values)

Research quality data products can be accessed using Earthdata Search:

• SMAP Soil Moisture Data

Near real-time (NRT) SMAP data are available through NASA’s Land, Atmosphere Near real-time Capability for EOS (LANCE) within 60 to 125 minutes after a satellite observation:

• SMAP NRT Data

Model Data

GRACE-DA-DM

Weekly soil moisture and groundwater drought indicators are available each week based on terrestrial water storage observations derived from Gravity Recovery and Climate Experiment (GRACE) satellite data and integrated with other observations, using a sophisticated numerical model of land surface water and energy processes, referred to as GRACE Data Assimilation for Drought Monitoring (GRACE-DA-DM).

• Groundwater and Soil Moisture Conditions from GRACE and GRACE-FO Data Assimilation through Earthdata Search

GMAO SMAP

NASA’S Global Modeling And Assimilation Office (GMAO), in collaboration with the University of Montana and NASA’s Jet Propulsion Laboratory, provides value-added Level 4 data products. These Level 4 datasets merge SMAP observations into physically-based numerical models of the land surface water, energy, and carbon cycles. Available Level 4 data include global, 9-km, 3-hourly estimates of surface and root zone soil moisture, surface and soil temperature, and land surface fluxes, along with algorithm diagnostics from the ensemble-based data assimilation system. Level 4 data also include global, 9-km, daily estimates of net ecosystem CO₂ exchange, component carbon stocks and fluxes, and sub-grid information broken down by plant functional types.

Near real-time SMAP imagery can be accessed and interactively explored using NASA Worldview:

• GEOS-5 SMAP soil moisture data

 These data products are available from Earthdata Search:

• GEOS-5 SMAP soil moisture data

LDAS

NASA, in collaboration with other agencies, has developed models of soil moisture content that incorporate satellite information with ground-based data (when ground-based data are available). The Land Data Assimilation System (LDAS) includes a global collection (GLDAS), a North American collection (NLDAS), National Climate Assessment - Land Data Assimilation System (NCA-LDAS), and a Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS). LDAS uses measurements including air temperature, precipitation, soil texture, and topography. GLDAS modeled data are available from January 1948 to present. NLDAS modeled datasets are available from January 1979 to present. FLDAS modeled datasets are available from January 1982 to present.

• NLDAS Soil Moisture Data
• GLDAS Soil Moisture Data

The NLDAS experimental drought monitor is derived from near real-time soil moisture output model data: 

• NLDAS Drought Monitor Soil Moisture

Soil MERGE (SMERGE) is a root-zone soil moisture product developed by merging NLDAS land surface model output with surface satellite retrievals from the ESA (European Space Agency) Climate Change Initiative. This data product contains root-zone soil moisture of 0-40 cm layer, Climate Change Initiative (CCI)-derived soil moisture anomalies of 0-40 cm layer, and a soil moisture data estimation flag.

• SMERGE in Earthdata Search

Using an online interactive tool called Giovanni, map visualizations of LDAS and SMERGE data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• NLDAS Soil Moisture
• GLDAS Soil Moisture
• FLDAS Soil Moisture
• NCA-LDAS Soil Moisture
• SMERGE Root Zone Soil Moisture

LDAS Soil Moisture data from GLDAS, NLDAS and FLDAS are available in Earthdata Search:

• LDAS components Soil Moisture data

SPoRT-LiS

The Short-term Prediction Research and Transition (SPoRT) project at NASA's Marshall Space Flight Center in Huntsville, AL, is a NASA- and NOAA-funded activity to transition experimental/quasi-operational satellite observations and research capabilities to the operational weather community to improve short-term weather forecasts on a regional and local scale.SPoRT-Land Information System (SPoRT-LiS) provides real-time 3km Land Information System data on the following parameters: Volumetric Soil Moisture, Relative Soil Moisture, Column-Integrated Relative Soil Moisture, and Green Vegetation Fraction.

SPoRT offers a Near Real-Time Viewer that includes SMAP datasets for the following regions:

• ENH Alaska (9km Enhanced)
• ENH CONUS (9km Enhanced)
• ENH East Africa (9km Enhanced)
• L2 Conus (Level 2)
• L2 East Africa (Level 2)

Reanalysis Data

MERRA-2

The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) provides data beginning in 1980. Due to the amount of historical data available, MERRA-2 data can be used to look for trends and patterns, as well as anomalies. There are several options available: hourly and monthly from 1980.

Using an online interactive tool called Giovanni, map visualizations of MERRA-2 Soil Moisture data products can be downloaded as PNG images, or as GeoTIFF or KMZ files; time-series data are available as CSV data files, and animations are in either webm video format or animated GIF images:

• MERRA-2 soil moisture data

MERRA-2 Soil Moisture data in Earthdata Search

• MERRA-2 Soil Moisture