Cross‐Calibration of FY‐3E/HEPD With SPE‐Selected GOES‐16/SGPS Observations

Abstract

The study performs on‐orbit cross‐calibration of the High‐Energy Proton Detector (HEPD) aboard the FY‐3E satellite in low Earth orbit using 12 solar proton events observed by the GOES‐16/Solar and Galactic Proton Sensor (SGPS) instrument in geostationary Earth orbit between July 2023 and November 2024. The effective energy and energy ranges of each channel on HEPD are determined by minimizing the differential proton flux residuals from both satellites. After the cross‐calibration, the fluxes between the HEPD channels and SGPS data show a Pearson Correlation Coefficient of over 0.85, and the Theil‐Sen linear fitting slopes range from 0.94 to 1.1. The median flux ratios for the integral flux in the energy ranges of 10–300 MeV, 30–300 MeV, 60–300 MeV, and 100–300 MeV are 1.17, 1.02, 1.17, and 1.14, respectively. Additionally, environmental disturbances, specifically variations in solar wind dynamic pressure (Psw) and disturbance storm time (Dst), significantly impact the consistency of cross‐satellite proton flux data between the HEPD and SGPS. A Psw >3 nPa and a Dst index <−50 nT provide effective constraints for data consistency, under which the two detectors exhibit generally consistent energy spectra. Based on the successful cross‐comparison and validation, FY‐3E satellite can be used for the monitoring and forecasting of solar proton flux, similar to the GOES satellites. In the future, it can provide high‐precision, cross‐platform consistent data inputs for critical applications such as solar proton event warnings, spacecraft radiation risk assessments, and magnetospheric cutoff rigidity modeling.