Cross Calibration of the GPS Constellation CXD Proton Data With GOES EPS. Issue 3 (30th March 2018)

• Record Type: Journal Article
• Authors: Carver, Matthew R.; Sullivan, John P.; Morley, Steven K.; Rodriguez, Juan V.
• Is Part Of: Space weather. Volume 16:Issue 3(2018)
• Page Start: 273
• Page End: 288
• Publication Date: 2018-03-30
• Subjects: Global Positioning System -- combined X‐ray dosimeter -- GOES; Space environment -- Periodicals; 551.509992
• DOI: 10.1002/2017SW001750
• Languages: English
• ISSNs: 1542-7390

Abstract

Abstract: Accurate proton flux measurements of the near‐Earth environment are essential to the understanding of many phenomena which have a direct impact on our lives. Currently, there is only a small set of satellites capable of performing these measurements which makes certain studies and analyses difficult. This paper details the capabilities of the Combined X‐ray Dosimeter (CXD), flown on 21 satellites of the Global Positioning System constellation, as it relates to proton measurements. We present a cross calibration of the CXD with the Energetic Particle Sensor (EPS) onboard the Geostationary Operational Environmental Satellite operated by the National Oceanic and Atmospheric Administration. By utilizing Solar Energetic Particle Events when both sets of satellites were operational we have orders of magnitude in flux and energy to compare against. Robust statistical analyses show that the CXD and Geostationary Operational Environmental Satellite flux calculations are similar and that for proton energies >30 MeV the CXD fluxes are on average within 20% of EPS. Although the CXD has a response to protons as low as 6 MeV, the sensitivity at energies below 20 MeV is reduced and so flux comparisons of these are generally worse. Integral flux values >10 MeV are typically within 40% of EPS. These calibrated CXD data sets will give researchers capabilities to study solar proton access to the inner magnetosphere down to L ~ 4 near the equatorial plane at high temporal cadence. Key Points: There are presently 21 operational CXD instruments continuously monitoring proton fluxes at a wide range of magnetic latitude and local time The CXD proton data have been cross calibrated against GOES EPS data Proton energies >20 MeV are well characterized by the CXD, and integral fluxes are typically within 20–40% of GOES EPS data