hide
Free keywords:
-
Abstract:
Understanding the dynamics of energetic electrons in the radiation belts is key to protect space borne equipment and astronauts on-board spacecraft missions. Therefore, global reconstruction of the near-Earth radiation environment should be available at all times and locations. Low Earth Orbit (LEO) satellites provide large data sets of the radiation belt region over a wide range of magnetic local times. However, the use of these data is complicated due to contamination of electron fluxes by protons and precipitating particles, leading to high variability of electron measurements, considerable instrumental errors and the need for background correction. In this study, we present a new intercalibration method for satellite measurements of energetic electrons in the radiation belts using data assimilation. We intercalibrate electron flux measurements of POES satellites against RBSP observations. For this, we use a reanalysis of the radiation belt region, obtained by assimilating RBSP and GOES electron data into 3-D Versatile Electron Radiation Belt (VERB-3D) code simulations via a standard Kalman filter. Since the reanalysis provides global reconstruction of the system, we can compare the POES data with our reanalysis and estimate the flux ratios at each time, location and energy. These ratios are averaged over time and space to obtain energy dependent recalibration coefficients. To validate our results, we perform a traditional conjunction study between POES and Van Allen probes. The conjunction coefficients and the DA estimated coefficients show very good agreement. The use of a data assimilative reanalysis significantly improves statistics and less data is necessary for the intercalibration.
