EnviroAtlas - Potential Evapotranspiration 1950 - 2099 for the Conterminous United States

The EnviroAtlas Climate Scenarios were generated from NASA Earth Exchange (NEX) Downscaled Climate Projections (NEX-DCP30) ensemble averages (the average of over 30 available climate models) for each of the four representative concentration pathways (RCP) for the contiguous U.S. at 30 arc-second (approx. 800 m2) spatial resolution. In addition to the three climate variables provided by the NEX-DCP30 dataset (minimum monthly temperature, maximum monthly temperature, and precipitation) a corresponding estimate of potential evapotranspiration (PET) was developed to match the spatial and temporal scales of the input dataset. PET represents the cumulative amount of water returned to the atmosphere due to evaporation from Earth’s surface and plant transpiration under ideal circumstances (i.e., a vegetated surface shading the ground and unlimited water supply). PET was calculated using the Hamon PET equation (Hamon, 1961) and CBM model for daylength (Forsythe et al. 1995) for the 4 RCPs (2.6, 4.5, 6.0, 8.5) and organized by season (Winter, Spring, Summer, and Fall) and annually for the years 2006 – 2099. Additionally, PET was calculated for the ensemble average of all historic runs and organized similarly for the years 1950 – 2005. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://cds.nccs.nasa.gov/nex/) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).