Trends in pan evaporation and actual evapotranspiration across the conterminous U.S.: Paradoxical or complementary?

Abstract

Pan evaporation ( ET pan ) has decreased at 64% of pans in the conterminous U.S. over the past half‐century. Comparing trends in ET pan and water budget‐derived actual evapotranspiration ( ET * a ), we observe the so‐called “Pan Evaporation Paradox,” which we confirm is no more than a manifestation of the complementarity between actual evapotranspiration ( ET a ) and potential evapotranspiration ( ET p ). Examining trends in the components of ET a —the radiative energy and regional advective budgets—we show that both components must be considered together to explain the relationship between ET pan and ET * a .