{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Mike Hobbins", "hasEmail": "mailto:mike.hobbins@noaa.gov"}, "description": "The data are a long-term (1980-present), daily reanalysis of reference evapotranspiration, covering the globe at a spatial resolution of 0.625\u00b0 Longitude x 0.5\u00b0 Latitude. Reference evapotranspiration is a measure of evaporative demand, or the \"thirst of the atmosphere\"--basically how much moisture from the surface could evaporate into overpassing air, assuming (i) that enough water is available to evaporate and (ii) the surface is covered with a specific reference crop that completely shades the ground (some other conditions also apply). For this dataset, reference evapotranspiration is derived from the daily implementation of the Penman-Monteith reference evapotranspiration equation (Monteith, 1965) as codified in the FAO-56 report (FAO, 1998), which is the international standard for reference evapotranspiration estimation. The equation is driven by data from the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2; Gelaro et al., 2017). The MERRA-2 input data are at a spatial resolution of 0.5 deg lat x 0.625 deg long; the reference evapotranspiration output data are at the same spatial resolution. There are two outputs, one for each reference crop: ETos is the reference evapotranspiration from a short crop (0.12-m grass); ETrs is the reference evapotranspiration from a long-crop (0.5-m alfalfa).", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P9IIQMV1", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.62548706d34e21f8276f4299.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_62548706d34e21f8276f4299", "keyword": ["USGS:62548706d34e21f8276f4299", "climatologyMeteorologyAtmosphere", "food-security", "geoscientificInformation", "long-term daily product", "reference evapotranspiration"], "modified": "2026-05-11T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-180.0000, -90.0000, 179.6875, 90.0000", "theme": ["geospatial"], "title": "Global reference evapotranspiration for food-security monitoring (ver. 2.3, April 2026)"}