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This study uses Landsat 5, 7, and 8 level 2 collection 2 surface temperature to examine habitat suitability conditions spanning 1985–2019, relative to the thermal tolerance of the endemic and endangered delta smelt (Hypomesus transpacificus) and two non-native fish, the largemouth bass (Micropterus salmoides) and Mississippi silverside (Menidia beryllina) in the upper San Francisco Estuary. This product was validated using thermal radiometer data collected from 2008 to 2019 from a validation site on a platform in the Salton Sea (RMSE = 0.78 °C, r= 0.99, R2= 0.99, p< 0.01, and n= 237). Thermally unsuitable habitat, indicated by annual maximum water surface temperatures exceeding critical thermal maximum temperatures for each species, increased by 1.5 km2yr–1for the delta smelt with an inverse relationship to the delta smelt abundance index from the California Department of Fish and Wildlife (r= −0.44, R2= 0.2, p< 0.01). Quantile and Theil–Sen regression showed that the delta smelt are unable to thrive when the thermally unsuitable habitat exceeds 107 km2. A habitat unsuitable for the delta smelt but survivable for the non-natives is expanding by 0.82 km2yr–1. Warming waters in the San Francisco Estuary are reducing the available habitat for the delta smelt.

Thermal infrared (TIR) data, acquired by instruments on several NASA satellite platforms, are primarily used to estimate the surface temperature/emissivity of the Earth's land surface. One such instrument launched on NASA's Terra satellite in 1999 is the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), which has a spatial resolution of 90 m. Using ASTER data, NASA/Jet Propulsion Laboratory recently released the most detailed emissivity map of the Earth termed the ASTER Global Emissivity Dataset (ASTER GED) that was acquired by processing millions of cloud free ASTER scenes from 2000 to 2008. The ASTER GEDv3 provides an average emissivity at ~100 m and ~1 km, while GEDv4 provides a monthly emissivity from 2000 to 2015 at ~5 km spatial resolution in the wavelength range between 8 and 12 µm. Validation with lab spectra from four desert sites resulted in an average absolute band error of ~1%, compared to current heritage MODIS products that had average absolute errors of 2.4% (Collection 4) and 4.6% (Collection 5). NASA/JPL released the first global ASTER emissivity map of Earth's surfaceASTER GED at 100 m resolution is 2500 times more detailed than any previous dataASTER GED will improve surface temperature and net longwave radiation estimates