About the Product

Scientists at NASA’s Goddard Space Flight Center generate groundwater and soil moisture drought indicators each week. They are based on terrestrial water storage observations derived from GRACE-FO satellite data and integrated with other observations, using a sophisticated numerical model of land surface water and energy processes. The drought indicators describe current wet or dry conditions, expressed as a percentile showing the probability of occurrence for that particular location and time of year, with lower values (warm colors) meaning dryer than normal, and higher values (blues) meaning wetter than normal. These are provided as both images and binary data files.

The Contiguous U.S. (CONUS) indicators are generated at 0.125 degree, while the Global Land indicators are at 0.25 degree resolution (Global/Africa/Asia/Australia/Europe/North America/South America areas above).

About the Forecast

Using the GRACE-FO based moisture conditions as a starting point, NASA scientists forecast groundwater and soil moisture wetness or drought 1, 2, and 3 months into the future. The model is driven into the future using downscaled seasonal meteorological forecasts from NASA’s GEOS-5 Earth system model. The resulting forecast maps describe wetness/drought conditions, expressed as a percentile showing the probability of occurrence within the period 1948-2014, with lower values (warm colors) meaning dryer than normal, and higher values (blues) meaning wetter than normal. These are provided as both images and binary data files.