Drivers of variability in evaporative demand in models and observations

Variations in reference evapotranspiration on monthly to annual to long-term trend timescales are examined in gridded observations and in CMIP5 climate models. In order to answer whether climate models are getting the correct drivers for reference ET changes, the sensitivities to the driving meteorological variables are computed along with the driving variances to understand why changes have taken place in the historic record, and how models are driving future changes. CMIP5 climate model projections are also investigated from the standpoint of reference ET drivers and regional features are discussed in the US.