Журнал дистанционного зондирования и ГИС

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Can the Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) Satellite Track Soil Moisture at the Macro-Climate Scale Across the Western United States?

Marisol Zepeda, Amanda Croteau, Christopher Potter

The ECOSTRESS satellite uses thermal infrared wavelengths to measure the temperature of the land surface and to calculate an Evaporative Stress Index (ESI). NASA’s ECOSTRESS mission was designed to support climate change research, since ESI can be an important indicator of the drought stress in terrestrial plant communities. We evaluated this satellite ESI for its capability to track changes in soil moisture measured at Unites States Department of Agriculture (USDA) stations in the western states. Soil water datasets from 2019 and 2020 from thirty stations in California, seven stations in Utah, three stations in Nevada, and two stations in Idaho were used for comparison of all daily average ESI images from ECOSTRESS. We also evaluated the ESI by comparing it to the reference potential Evapotranspiration (ETo) at the stations operated by CIMIS (California Irrigation Management Information). Correlation results showed that ECOSTRESS ESI can track soil moisture changes most closely at 4 inch, 8 inch, and 20 inch (10 cm, 20 cm, and 50 cm) soil depths for southern California desert station locations, where the predominant land cover was shrubland, and in the Great Basin region at 2 inch and 8 inch soil layers. However, ESI failed to correlate with soil moisture measured at many station locations in the Sierra-Nevada mountain region at any soil depth. ECOSTRESS ESI also failed to reliably track measured PET at any CIMIS stations. Several explanations were explored for this lack of predictive capacity of ECOSTRESS ESI as a drought indicator in the western United States.