The USGS collects evapotranspiration data needed by Federal, State, and local agencies for planning and operating water-resources projects and regulatory programs. Over 20 years of reference evapotranspiration (RET) and potential evapotranspiration (PET) were computed for all five water management districts in the State of Florida. These maps represent potential daily atmospheric water use at 2-km resolution from June 1, 1995, to December 31, 2015. Incoming solar radiation (insolation) is a primary driver of ET in Florida. Insolation maps from the Geostationary Operational Environmental Satellite (GOES) are used to compute PET and RET, and the insolation maps are well calibrated by using ground-based pyranometers. As expected, PET and RET generally increase from north to south due to enhanced solar radiation in south Florida. Key hydrologic features that affect regional weather patterns, such as Lake Okeechobee and the Gulf of Mexico, also are reflected in the results. Planned enhancements include (1) a historical extension to 1985, (2) use of spatially continuous forecast or reanalysis model fields to improve representations of temperature, humidity, and wind speed, and (3) incorporation of “blue-sky” albedos from the Moderate Resolution Imaging Spectroradiometer (MODIS) to improve estimates of net radiation.
