Evapotranspiration (ET): 1985

Evapotranspiration data developed using METRIC (Mapping EvapoTranspiration at high Resolution with Internalized Calibration). METRIC is an image-processing model for computing ET data for large areas from satellite images. METRIC computes a complete radiation and energy balance for the earth's surface along with fluxes of sensible heat and ET. METRIC uses digital image data collected by Landsat or other remote sensing satellites measuring visible, near-infrared, and thermal infrared radiation. METRIC also incorporates USBR AgriMet weather data into the modeling process. Dr Rick Allen, Dr. M. Tasumi, and Dr. R. Trezza, of the University of Idaho, developed METRIC by making refinements to the Surface Energy Balance Algorithm for Land (SEBAL). METRIC ET data in Idaho was developed using Landsat 5, 7 and 8 data. Most data are in the ERDAS Imagine file format. Filenames include the path and row of the Landsat images used and the range of dates for seasonal ET data (e.g. p40r30_20000301to1031season_et.img is Landsat path 40 row 30, seasonal ET for the growing season of 3/1/2000 to 10/31/2000). Monthly images show the month number (e.g. p40r30_200007_et.img is for July of 2000). Usually about 8 images (one per month) are processed to develop a seasonal ET image. ET units are millimeters.