GOES‐R Series X‐Ray Sensor (XRS): 2. On‐Orbit Measurements and Calibrations

Abstract An X‐Ray Sensor (XRS) has been onboard each of the National Oceanic and Atmospheric Administration (NOAA) Geostationary Operational Environmental Satellites (GOES) since 1975. XRS measures full‐disk soft X‐ray irradiance in two wavelength bands, 0.05–0.4 nm and 0.1–0.8 nm. The measurements are used to define solar flare magnitudes, to provide first alerts of major space weather events, and to support a variety of solar and space weather research. The XRS sensors on the GOES‐R series (GOES‐16 through GOES‐19) have a new instrument design with Si photodiodes instead of ionization cells, multiple channels to provide an increased dynamic range, the use of quadrant photodiodes for real‐time flare location measurements, and improved pre‐flight radiometric calibrations. The in‐flight solar XRS measurements and data products from GOES‐16 through GOES‐19 are presented here, and the design and pre‐flight calibration results are presented in Woods et al. (2024), https://doi.org/10.1029/2024ja032925 . In addition to improved 1‐s and 1‐min irradiance data products, a variety of new XRS data products are provided including a flare summary, flare location, and a multi‐decade composite flare report.