Comparison of Satellite-Based Soil Moisture Estimates
and Rainfall Data for a New Mexico Watershed

Background Study Area Data Methods Results & Conclusions

Soil Moisture Data

Soil moisture data were obtained from the Soil Moisture Active Passive (SMAP) mission onboard a NASA (National Aeronautics and Space Administration) satellite (https://smap.jpl.nasa.gov/). Measurements are based on natural microwave emissions recorded by a radiometer. SMAP data is gridded with a spatial resolution of 81 km² and a temporal resolution 11-37 hours. Figure 2 shows 31 soil moisture estimates for the month of August 2018.

Figure 2: SMAP soil moisture estimates for the study area, August 1-31, 2018 (dates based on UTC).

Precipitation Data

Rainfall data were obtained from nine tipping bucket rain gages (Figure 3, yellow circles) and Next-Generation Radar (NEXRAD) Quantitative Precipitation Estimation (QPE) products (https://www.ncdc.noaa.gov/data-access/radar-data/nexrad). Gage data represent point measurements of precipitation in 0.01 inch (0.254 mm) increments with a temporal resolution of 5 minutes. Radar derived rainfall estimates are gridded, whereby grid resolution decreases with distance from the radar tower. Temporal resolution of radar data ranges from 4-15 minutes.

Figure 3: NEXRAD precipitation accumulation for eight storms in the study area during August 2018 (dates based on UTC).