Description

Groundwater is a vital resource, especially in arid regions where surface water is limited. The U.S. Geological Survey (USGS) reports approximately 82 billion gallons of groundwater are withdrawn daily in the U.S. for domestic, irrigation, industrial, mining, thermoelectric, livestock, and aquaculture uses. 

According to the National Groundwater Association (NGWA), groundwater accounts for about 29% of total U.S. water usage; about two thirds of that groundwater is used for irrigation. Aquifers in certain regions of the world are being depleted by unsustainable groundwater pumping to support irrigated agriculture, including in southern High Plains and Central Valley aquifers in the U.S., northern India, the North China Plain, and parts of the Middle East. 

The Gravity Recovery and Climate Experiment (GRACE, 2002–2017) and GRACE Follow-On (GRACE-FO, 2018–present) satellite missions -- supported by NASA and the German Research Centre for Geosciences (GFZ) -- provide monthly estimates of changes in terrestrial water storage (the sum of groundwater, soil moisture, surface waters, snow, and ice) at spatial resolutions no better than about 150,000 km² at mid-latitudes. While useful for detection of large-scale changes, the coarse resolution limits regional-scale groundwater assessments. 

There are, however, groundwater products with higher spatial resolutions, which can be useful for finer scale groundwater monitoring. A new product from Observational Products for End-Users from Remote Sensing Analysis (OPERA), provides surface displacement products (DISP) for North America indicating subsidence due to groundwater withdrawal based on Synthetic Aperture Radar (SAR) from Sentinel-1 at 30 m² (and from NISAR as of next year). In addition, NASA's Global Land Data Assimilation System (GLDAS) assimilates GRACE/GRACE-FO data into a land surface model along with other, higher resolution inputs, producing daily outputs on a 0.25° (~25 km) grid. 

This three-part training will focus on an overview of GRACE/GRACE-FO data, OPERA-DISP data, and GLDAS groundwater data for assessing seasonal to interannual groundwater changes at various spatial scales. The training will provide hands-on experience in accessing and analyzing these products for applications.

Prerequisites

• Groundwater Monitoring using Observations from NASA’s Gravity Recovery and Climate Experiment (GRACE) Missions

Objectives

By the end of this training attendees will be able to:

• Identify characteristics of groundwater quantity datasets from GRACE/FO, OPERA, and GLDAS.
• Access, analyze, and visualize GRACE/FO data to monitor seasonal to interannual changes in large-scale total terrestrial water storage.
• Access, analyze, and visualize GLDAS data to monitor seasonal to interannual changes in groundwater using at regional scale.
• Map surface subsidence related to groundwater extraction with OPERA Displacement (DISP) data.
• Utilize groundwater products from these datasets at multiple spatial/temporal scales to make decisions in a variety of applications, such as monitoring drought and flood conditions, planning groundwater resources for irrigation.

Target Audience

• Water resource, drought and flood managers, and irrigation managers from federal, state, and local government agencies, NGOs, and private sector organizations, both domestically and internationally.
• Academic faculty and students, mining planners, groundwater recharge and water harvesting planners.

Course Format

• Three, 2-hour parts
• Two identical sessions will be hosted at two different times of day for each part:
  • Session A: 11:00 a.m. to 1:00 p.m. EDT (UTC-4)
  • Session B: 2:00 p.m. to 4:00 p.m. EDT (UTC-4)
• Each part will include a 30-minute live Q&A.
• Those who attend all parts and complete the homework by the due date will receive a certificate of attendance.

Sessions

Part 1: Overview and Analysis of NASA Terrestrial Water Storage Data from GRACE/GRACE-FO

Thursday, April 23, 2026

• Overview of GRACE/GRACE-FO missions
• GRACE/FO data products
• Data applications, benefits, and limitations
• Select and visualize maps and time series of terrestrial water storage changes
• Using GRACE/FO Interactive Browser
• Case study: GRACE data access, analysis, and visualization
• Summary

ARSET Instructors

Amita Mehta

Guest Instructors

Matthew Rodell (NASA GSFC)

Part 2: Overview and Applications of GLDAS Groundwater Data Products at Regional Scale

Tuesday, April 28, 2026

• Background and description
• Motivation for GRACE data assimilation
• GLDAS groundwater data evaluation
• Examples of data applications, benefits, and limitations
• Giovanni/Earthdata search
• Exercise: GLDAS data analysis
• Summary

ARSET Instructors

Amita Mehta

Guest Instructor

Matthew Rodell (NASA GSFC)

Part 3: Overview and Applications of OPERA-DISP to Monitor Groundwater Changes

Thursday, April 30, 2026

• Background of SAR data and OPERA
• Description and interpretation of DISP data for monitoring groundwater changes
• Data applications, benefits, and limitations
• OPERA Displacement Portal
• OPERA data analysis with Jupyter Notebook
• Case study: OPERA-DISP data access, visualization, and interpretation
• Summary

ARSET Instructor

Amita Mehta

Guest Instructor

Eric Fielding (NASA JPL/Caltech)