Simplified Surface Energy Balance Actual Evapotranspiration data for the Conterminous U.S.

Actual ET (ETa) is produced using the operational Simplified Surface Energy Balance (SSEBop) model (Senay and others, 2013) for the period 2000 to present. The SSEBop setup is based on the Simplified Surface Energy Balance (SSEB) approach (Senay and others, 2007, 2011) with unique parameterization for operational applications. It combines ET fractions generated from remotely sensed MODIS thermal imagery, acquired every 8 days, with reference ET using a thermal index approach. The unique feature of the SSEBop parameterization is that it uses pre-defined, seasonally dynamic, boundary conditions that are unique to each pixel for the hot/dry and cold/wet reference points. Reference: Senay, G. B., Bohms, S., Singh, R. K., Gowda, P. H., Velpuri, N. M., Alemu, H., et al. (2013). Operational evapotranspirationmapping using remote sensing andweather datasets: A new parameterization for the SSEB approach. Journal of the American Water Resources Association, 1-2013;15, http://dx.doi.org/10.1111/jawr.12057. Reference: Velpuri, N. M., Senay, G. B., Singh, R. K., Bohms, S., and Verdin, J. P.: A comprehensive evaluation of two MODIS evapotranspiration products over the conterminous United States: Using point and gridded FLUXNET and water balance ET, Remote Sensing of Environment, 139, 35-49, http://dx.doi.org/10.1016/j.rse.2013.07.013, 2013.