Evapotranspiration data from eddy-covariance flux-tower measurements and Landsat imagery in California’s Sierra Nevada from 1985 to 2019

The gridded annual evapotranspiration (ET) from 1985 to 2019 were calculated based on the correlations between eddy-covariance flux-tower measurements of annual evapotranspiration and satellite imagery derived Normalized Difference Vegetation Index (NDVI). Annual ET observations from 12 flux-towers across the Sierra Nevada and Southern California were collected from 2001 to 2016, resulting 97 site-years of ET observations in five main vegetation types (Evergreen Needleleaf Forest, Grasslands, Mixed Forest, Open Shrublands, and Woody Savannas). The NDVI was calculated at 30-m resolution from USGS Landsat Collection Tier 1 surface reflectance over the entire California and aggregated to annual mean values for each water year (Oct. to Sept.) from 1985 to 2019. The gridded annual ET was calculated at 30 m spatial resolution using the exponential relationship between NDVI and ET derived from flux-tower sites.