Calibration and Validation of Earth-Observing Sensors Using The Radiometric Calibration Test Site (RadCaTS) at Railroad Valley, Nevada, USA

The Radiometric Calibration Test Site (RadCaTS) was developed by the University of Arizona to provide satellite operators and the scientific community with daily ground-based data that are appropriate for the radiometric calibration and surface reflectance product validation of Earth-observation sensors. It is located at Railroad Valley, Nevada, USA, which has been used by the University of Arizona since 1996. The primary goal of RadCaTS is to provide data that can be used for the independent, accurate, and timely analysis of both the radiometric calibration and surface reflectance validation of Earth-observation sensors that operate in the solar-reflective region (400 nm to 2500 nm). RadCaTS is currently being used to monitor low-Earth orbit sensors such as Terra and Aqua MODIS, SNPP and NOAA-20 VIIRS, Landsat 8 OLI, Sentinel-2A and -2B MSI, Sentinel-3A and -3B OLCI and SLSTR, as well as geosynchronous sensors such as GOES-16 and ‑17 ABI. RadCaTS is currently one of four automated test sites that make up the CEOS WGCV IVOS Radiometric Calibration Network (RadCalNet), which seeks to harmonize the ground-based calibration and validation measurements from international organizations. This work presents current results from RadCaTS, as well as a comparison with results obtained from the RadCalNet data portal, which became publicly available at no cost to registered users in June 2018.