Drought monitoring and early warning requires a convergence of evidence from varied sources with enough lead time for mitigation and other management actions. Soil moisture is a key state variable that controls the partitioning of precipitation into runoff and the rate of landscape evapotranspiration (ET). To record soil moisture measurements, NASA developed the Soil Moisture Active Passive (SMAP) satellite mission, which was designed to measure the amount of water in the upper 2 inches (5 cm) of soil everywhere on the Earth’s surface. SMAP science objectives are to understand processes that link the terrestrial water, energy, and carbon cycles; to estimate global water and energy fluxes at the land surface; to quantify net carbon flux in boreal landscapes; to enhance weather and climate forecast skill; and to develop improved flood prediction and drought monitoring capabilities.
Through the early adopters program, the DOI North Central Climate Science Center (NC CSC) in conjunction with the USGS Earth Resources and Observation Science (EROS) Center was able to quickly evaluate SMAP soil moisture data products soon after the launch of the sensor on January 31, 2015. Results show that SMAP soil moisture correlated well with in situ soil moisture, gridded rainfall, and model-derived evapotranspiration, building confidence in SMAP’s utility for drought monitoring and early warning applications. This research is published as: Velpuri, N.M., Senay, G.B., Morisette, J.T. (2016). Evaluating New SMAP Soil Moisture for Drought Monitoring in the Rangelands of the US High Plains, Rangelands, 38:4, p183-190.
Study area showing hydrologic units (HUC8 watersheds) that are dominated by grasslands and shrublands. Stars represent locations of United States Climate Reference Network (USCRN) soil moisture observation sites used in the study. Background image is 8-day average SMAP Soil Moisture fields summarized for March 30–April 7, 2015.