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Evaluating the temperature difference parameter in the SSEBop model with satellite observed land surface temperature data

August 20, 2019

The Operational Simplified Surface Energy Balance (SSEBop) model uses the principle of satellite psychrometry to produce spatially explicit actual evapotranspiration (ETa) with remotely sensed and weather data. The temperature difference (dT) in the model is a predefined parameter quantifying the difference between surface temperature at bare soil and air temperature at canopy level. Because dT is derived from the average-sky net radiation based primarily on climate data, validation of the dT estimation is critical for assuring a high-quality ETa product. We used the Moderate Resolution Imaging Spectroradiometer (MODIS) data to evaluate the SSEBop dT estimation for the conterminous United States. MODIS data (2008–2017) were processed to compute the 10-year average land surface temperature (LST) and normalized difference vegetation index (NDVI) at 1 km resolution and 8-day interval. The observed dT (dTo) was computed from the LST difference between hot (NDVI < 0.25) and cold (NDVI > 0.7) pixels within each 2° × 2° sampling block. There were enough hot and cold pixels within each block to create dTo timeseries in the West Coast and South-Central regions. The comparison of dTo and modeled dT (dTm) showed high agreement, with a bias of 0.8 K and a correlation coefficient of 0.88 on average. This study concludes that the dTm estimation from the SSEBop model is reliable, which further assures the accuracy of the ETa estimation.

Citation Information

Publication Year 2019
Title Evaluating the temperature difference parameter in the SSEBop model with satellite observed land surface temperature data
DOI 10.3390/rs11161947
Authors Lei Ji, Gabriel B. Senay, Naga Manohar Velpuri, Stefanie Kagone
Publication Type Article
Publication Subtype Journal Article
Series Title Remote Sensing
Index ID 70222960
Record Source USGS Publications Warehouse
USGS Organization Earth Resources Observation and Science (EROS) Center