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Description

M2T1NXCHM (or tavg1_2d_chm_Nx) is an hourly time-averaged 2-dimensional data collection in Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). This collection consists of assimilated carbon monoxide and ozone diagnostics, such as properties of carbon monoxide (column burden, emission, chemical production, and surface concentration), and total column ozone. The data field is time-stamped with the central time of an hour starting from 00:30 UTC, e.g.: 00:30, 01:30, … , 23:30 UTC.

MERRA-2 is the latest version of global atmospheric reanalysis for the satellite era produced by NASA 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 ~3 weeks after the end of a month.

Data Reprocessing: Please check “Records of MERRA-2 Data Reprocessing and Service Changes” linked from the “Documentation” tab on this page. Note that a reprocessed data filename is different from the original file.

MERRA-2 Mailing List: Sign up to receive information on reprocessing of data, changing of tools and services, as well as data announcements from GMAO. Contact the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov) to be added to the list.

Questions: If you have a question, please read "MERRA-2 File Specification Document", “MERRA-2 Data Access – Quick Start Guide”, and FAQs linked from the ”Documentation” tab on this page. If that does not answer your question, you may post your question to the NASA Earthdata Forum (forum.earthdata.nasa.gov) or email the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov).

Version Description

The GEOS-5 model version used for processing MERRA-2

Product Summary

Platforms
MERRA-2
Instruments
NOT APPLICABLE
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Spatial Resolution
0.625 Decimal Degrees x 0.5 Decimal Degrees
Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
1980-01-01 to Present
Data Partner
Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Terrestrial Information Systems Laboratory, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/TISL/GESDI
Concept ID
C1276812831-GES_DISC
Data State
ACTIVE
Number of Files/Granules
16893
Processing Level
4
Published
Updated
Science Keywords
Atmospheric Carbon Monoxide ,
Carbon Monoxide ,
Atmospheric Ozone

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Global Modeling And Assimilation Office, & Pawson, S. (2015). MERRA-2 tavg1_2d_chm_Nx: 2d,3-Hourly,Time-Averaged,Single-Level,Assimilation,Carbon Monoxide and Ozone Diagnostics V5.12.4 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/3RQ5YS674DGQ Date Accessed: 2026-05-18

Documents

Publications Citing This Dataset

Filters
Title Year Author Topic
SEISMO-VRE: A tool for a multiparametric and multidisciplinary study of an earthquake Marchetti, Dedalo, Bailo, Daniele, Falcone, Giuseppe, Michalek, Jan, Paciello, Rossana, Piscini, Alessandro Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Heat Flux, Air Temperature, Skin Temperature, Specific Humidity, Water Vapor, Precipitation Rate, Snow/Ice, Evaporation, Latent Heat Flux, Latent Heat Flux, Sensible Heat Flux, Diffusion, Surface Winds, Wind Speed, U/V Wind Components, Wind Stress, Wind Stress, Surface Roughness, Planetary Boundary Layer Height, Ice Fraction, Surface Pressure, Surface Winds, Geopotential Height, Total Precipitable Water, Cloud Liquid Water/Ice, Atmospheric Water Vapor, Oxygen Compounds, Potential Temperature, Potential Temperature, Air Mass/Density, Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone
Incorporating nonseismicity precursors into earthquake probabilistic forecasting model Zhang, Yiqun, Han, Peng, Chen, Hongyan, Zhan, Chengxiang, Niu, Yuanyuan, Zhuang, Jiancang, Zhu, Kaiguang Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone
Spatial analysis of cardiopulmonary disease risks linked to air pollution in Brazil Moore, Julia Placido, Will, Robson, Bastos, Camilo Ribeiro, Requia, Weeberb J., Hoinaski, Leonardo Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone
Sensor-generic adjacency-effect correction for remote sensing of coastal Wu, Yulun, Knudby, Anders, Pahlevan, Nima, Lapen, David, Zeng, Chuiqing Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone
Emissions from Military Training: Evidence from Australia Lee, Wang-Sheng, Tran, Trang Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Heat Flux, Air Temperature, Skin Temperature, Specific Humidity, Water Vapor, Precipitation Rate, Snow/Ice, Evaporation, Latent Heat Flux, Latent Heat Flux, Sensible Heat Flux, Diffusion, Surface Winds, Wind Speed, U/V Wind Components, Wind Stress, Wind Stress, Surface Roughness, Planetary Boundary Layer Height, Ice Fraction, Surface Pressure, Surface Winds, Geopotential Height, Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone
Exploring high-resolution near-surface CO concentrations based on Himawari-8 top-of-atmosphere radiation data: Assessing the distribution of city-level CO hotspots ... Chen, Bin, Hu, Jiashun, Song, Zhihao, Zhou, Xingzhao, Zhao, Lin, Wang, Yixuan, Chen, Ruming, Ren, Yuxiang Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone, Population Size, Atmospheric Chemistry, Carbon And Hydrocarbon Compounds, Air Quality, Atmospheric Temperature, Surface Temperature, Atmospheric Pressure, Surface Pressure, Atmospheric Water Vapor, Water Vapor Indicators, Water Vapor, Carbon Monoxide Profiles, Land Use/Land Cover Classification, RADAR IMAGERY, Terrain Elevation, Digital Elevation/Terrain Model (DEM)
Brazilian Atmospheric InventoriesBRAIN: a comprehensive database of air quality in Brazil Hoinaski, Leonardo, Will, Robson, Ribeiro, Camilo Bastos Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone, Aerosol Backscatter, Aerosol Radiance, Cloud Condensation Nuclei, Nitrate Particles, Trace Gases/Trace Species, Atmospheric Emitted Radiation, Emissivity, Optical Depth/Thickness, Radiative Flux, Reflectance, Transmittance, Atmospheric Stability, Humidity, Total Precipitable Water, Water Vapor Profiles, Cloud Condensation Nuclei, Cloud Droplet Concentration/Size, Cloud Liquid Water/Ice, Cloud Optical Depth/Thickness, Cloud Asymmetry, Cloud Ceiling, Cloud Frequency, Cloud Height, Cloud Top Pressure, Cloud Top Temperature, Cloud Vertical Distribution, Cloud Emissivity, Cloud Radiative Forcing, Cloud Reflectance, Rain Storms
Non-linear associations between meteorological factors, ambient air pollutants and major mosquito-borne diseases in Thailand Tewari, Pranav, Ma, Pei, Gan, Gregory, Janhavi, A., Choo, Esther Li Wen, Koo, Joel Ruihan, Dickens, Borame Lee, Lim, Jue Tao Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone
Very-Short-Term Variations of Sea Surface and Atmospheric Parameters Before the Ms 6.2 Zhangbei (China) Earthquake in 1998 Liu, Yingjia, Wu, Lixin, Qi, Yuan, Ding, Yifan Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone, Pressure Thickness, Surface Pressure, Tropospheric Ozone, Air Mass/Density
Long-term variation in aerosol lidar ratio in Shanghai based on Raman lidar measurements Liu, Tongqiang, He, Qianshan, Chen, Yonghang, Liu, Jie, Liu, Qiong, Gao, Wei, Huang, Guan, Shi, Wenhao, Yu, Xiaohong Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Atmospheric Carbon Monoxide, Carbon Monoxide, Atmospheric Ozone
Incorporating gridded concentration data in air pollution back trajectories analysis for source identification dos Santos, Otavio Nunes, Hoinaski, Leonardo Aerosols, Aerosol Extinction, Aerosol Optical Depth/Thickness, Angstrom Exponent, Aerosol Particle Properties, Carbonaceous Aerosols, Dust/Ash/Smoke, Organic Particles, Sulfate Particles, Sulfur Oxides, Sulfur Compounds, Sulfate, Sulfur Dioxide, Sulfur Oxides, Particulate Matter, Dimethyl Sulfide, Black Carbon, Sea Salt, PARTICULATE MATTER (PM 2.5), PARTICULATE MATTER (PM 1.0), PARTICULATE MATTER (PM 10), Geopotential Height, Altitude, Surface Temperature, Skin Temperature, Upper Air Temperature, Dew Point Temperature, Air Temperature, Cloud Top Temperature, Atmospheric Winds, Surface Winds, U/V Wind Components, Upper Level Winds, U/V Wind Components, Vertical Wind Velocity/Speed, Atmospheric Pressure, Sea Level Pressure, Cloud Top Pressure, Sea Level Pressure, Surface Pressure, Specific Humidity, Total Precipitable Water, Cloud Liquid Water/Ice, Atmospheric Water Vapor, Atmospheric Ozone, Oxygen Compounds, Boundary Layer Winds, Total Ozone, Atmospheric Carbon Monoxide, Carbon Monoxide
Using networked Pandora observations to capture spatiotemporal changes in total column ozone associated with stratosphere-to-troposphere transport Robinson, J., Kotsakis, A., Santos, F., Swap, R., Knowland, K.E., Labow, G., Connors, V., Tzortziou, M., Abuhassan, N., Tiefengraber, M., Cede, A. Geopotential Height, Altitude, Surface Temperature, Skin Temperature, Upper Air Temperature, Dew Point Temperature, Air Temperature, Cloud Top Temperature, Atmospheric Winds, Surface Winds, U/V Wind Components, Upper Level Winds, U/V Wind Components, Vertical Wind Velocity/Speed, Atmospheric Pressure, Sea Level Pressure, Cloud Top Pressure, Sea Level Pressure, Surface Pressure, Specific Humidity, Total Precipitable Water, Cloud Liquid Water/Ice, Atmospheric Water Vapor, Atmospheric Ozone, Oxygen Compounds, Boundary Layer Winds, Total Ozone, Potential Vorticity, Vertical Profiles, Relative Humidity, Ozone Profiles, Atmospheric Carbon Monoxide, Carbon Monoxide
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Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
COCL COCL kg m-2 float32 999999986991104 N/A 1 0
COEM COEM kg m-2 s-1 float32 999999986991104 N/A 1 0
COLS COLS kg m-2 s-1 float32 999999986991104 N/A 1 0
COPD COPD kg m-2 s-1 float32 999999986991104 N/A 1 0
COSC COSC 1e-9 float32 999999986991104 N/A 1 0
lat lat degrees_north float64 N/A N/A N/A N/A
lon lon degrees_east float64 N/A N/A N/A N/A
LWI LWI 1 float32 999999986991104 N/A 1 0
time time minutes since 2025-01-01 00:30:00 int32 N/A N/A N/A N/A
TO3 TO3 Dobsons float32 999999986991104 N/A 1 0
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