Water balance evapotranspiration (2002-2015 average) and bias adjustment factor for SSEBop ET across HUC8 basins in the conterminous United States

The water balance equivalence (WABE) method for reducing biases from remote sensing-derived evapotranspiration (RSET) products for large area applications is proposed and implemented across eight-digit hydrologic unit code (HUC8) basins in the conterminous United States (CONUS). These data support the findings of the WABE method that includes climatology (2002-2015 average) observed water balance ET (WBET), synthetic WBET, and bias adjustment factor (BAF) for SSEBop ET for HUC8 basins. The synthetic WBET filled the spatial gaps of observed WBET, constituting 44% of CONUS HUC8 basins, with estimations within 2% at the CONUS and between 1-12% across 18 regions in CONUS. After implementing HUC8-scale bias adjustment factors from the WABE method to the flux tower scale, SSEBop ET showed an overall bias reduction from 10% to 6% across 37 sites. The WABE method provides a path towards integration of in-situ ET for improving the accuracy of RSET products and supporting accurate basin water budgets and water management decisions.