SPATIOTEMPORAL PATTERNS OF POTENTIAL EVAPOTRANSPIRATION, PRECIPITATION, AND THE NET ATMOSPHERIC WATER BALANCE OVER FLORIDA

The opposing atmospheric fluxes of evapotranspiration (ET) and precipitation (P) are the primary determinants of water available to a watershed for runoff and infiltration. Potential evapotranspiration (PET) is commonly used in hydrologic analyses as the upper limit of ET under conditions of ample water availability. Thus, the difference between P and PET provides an estimate of minimally-available atmospheric water for a watershed. Spatiotemporal estimates (daily, 2-km) of PET throughout the State of Florida from 1995 to the present have been computed through integration of satellite- and field-derived meteorological data. In combination with gridded precipitation data derived from the PRISM product, the spatiotemporal interplay of P and PET can be explored. In addition to examining the geographic and temporal patterns of P, PET, and P – PET, specific research questions include: 1) the relative strength of P versus PET in determining spatiotemporal patterns of P – PET, 2) the relation of the magnitude and patterns of P, PET, and P – PET to El Niño episodes, 3) definition of the statistical structure of P, PET, and P – PET suitable for uncertainty analyses, and 4) relation between watershed-scale PET and ET.