Solar Radiation and Climate Experiment (SORCE) X-Ray Photometer System (XPS): Final Data-Processing Algorithms

• Published in: Solar physics Vol. 297; no. 5
• Main Authors: Woods, Thomas N., Elliott, Joshua
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.05.2022; Springer Nature B.V
• Subjects: Algorithms; Astrophysics and Astroparticles; Atmospheric Sciences; Climate monitoring; Cubesat; Data processing; Hydrogen; Ionosphere; Irradiance; Mesosphere; Photodegradation; Photometers; Physics; Physics and Astronomy; Radiation; Signal processing; Solar activity; Solar irradiance; Solar observatories; Solar physics; Solar radiation; Solar spectral irradiance; Solar x-rays; Space Exploration and Astronautics; Space missions; Space Sciences (including Extraterrestrial Physics; Spacecraft; The Solar Radiation and Climate Experiment (SORCE) Mission: Final Calibrations and Data Products; Thermosphere; X ray photoelectron spectroscopy; X-rays; Solar irradiance; Instrument effects; Solar-cycle observations
• ISSN: 0038-0938; 1573-093X; 1573-093X
• DOI: 10.1007/s11207-022-01997-4

The X-ray Photometer System (XPS) is one of four instruments onboard NASA’s Solar Radiation and Climate Experiment (SORCE) mission. The SORCE spacecraft operated from 2003 to 2020 to provide key climate-monitoring measurements of total solar irradiance (TSI) and solar spectral irradiance (SSI). The XPS is a set of photometers to measure the solar X-ray ultraviolet (XUV) irradiance shortward of 34 nm and the bright hydrogen emission at 121.6 nm. Each photometer has a spectral bandpass of about 7 nm, and the XPS measurements have an accuracy of about 20%. The updates for the final data-processing algorithms for the XPS solar-irradiance data products are described. These processing updates include improvements for the instrumental corrections for background signal, visible-light signal, and degradation trending. Validation of these updates is primarily with measurements from a very similar XPS instrument onboard NASA’s Thermosphere-Ionosphere-Mesosphere-Energetics-Dynamics (TIMED) mission. In addition, the XPS Level 4 spectral model has been improved with new reference spectra derived with recent XUV observations from NASA’s Solar Dynamics Observatory (SDO) and Miniature X-ray Solar Spectrometer (MinXSS) cubesat.