Validation of the effect of cross‐calibrated GOES solar proton effective energies on derived integral fluxes by comparison with STEREO observations

Abstract

The derivation of integral fluxes from instrument coincidence rates requires accurate knowledge of their effective energies. Recent cross calibrations of GOES with the high‐energy‐resolution Interplanetary Monitoring Platform (IMP) 8 Goddard Medium Energy Experiment (GME) (Sandberg et al., Geophys. Res. Lett, 41, 4435, 2014a) gave significantly lower effective energies than those currently used by the NOAA Space Weather Prediction Center to calculate solar proton integral fluxes from GOES rates. This implies systematically lower integral fluxes than currently produced. This paper quantifies the differences between the current and the cross‐calibrated GOES integral fluxes and validates the latter. Care is taken to rule out the spectral resolution of the measurements or different integration algorithms as major contributors to differences in the magnitudes of the derived integral fluxes. The lower effective energies are validated by comparison with the independent, high‐resolution observations by the STEREO Low‐Energy Telescope (LET) and High‐Energy Telescope (HET) during the December 2006 solar proton events. The current GOES product is similar to the >10 MeV integral fluxes recalculated by using the Sandberg et al. [] effective energies but is substantially greater at higher energies. (The median ratios of the current to the recalculated fluxes are 1.1 at >10 MeV, 1.7 at >30 MeV, 2.1 at >60 MeV, and 2.9 at >100 MeV.) By virtue of this validation, the cross‐calibrated GOES integral fluxes should be considered more accurate than the current NOAA product. The results of this study also demonstrate good consistency between the two long‐term IMP 8 GME and STEREO LET and HET solar proton data sets.

Updated Model of the Solar Energetic Proton Environment in Space

“…Comparisons of these outputs with ESP "Design Limit" and CREME96 spectra indicate the the CREME96 output might most appropriately be replaced by a 1-in-100-year SPE. Differences are well explained by updated data processing (Sandberg et al, 2014;Rodriguez et al, 2017) and the SAPPHIRE statistical approach creating envelope output spectra contrasting with the CREME96 approach basing outputs on the fluxes from a single SPE. Comparison with ACE/EPAM data shows differences with SAPPHIRE model proton peak flux outputs at lower energies outside the core model energy range (i.e.…”

“…This energy calibration replaces previous calibration performed on the fluxes which may use corresponding calibration data from IMP-8/GME in the wrong energy range. Recent validation of derived integral proton fluxes from RDSv2 has been performed by Rodriguez et al (2017).…”

Two solar proton fluence models based on ground level enhancement observations

“…Recently, Sandberg et al (2014) developed a method for cross-calibrating the medium energy GOES/EPS channels with corresponding channels of the science-level IMP-8/GME instrument. The effect of this cross-correlation was validated by Rodriguez et al (2017) using STEREO observations (Mewaldt et al, 2008;von Rosenvinge et al, 2008). Sandberg et al (2014) also noted some problems with the low energy IMP-8 data, attributed to the gradual failing of the LED instrument between 1984 and 1990.…”

Space environment data acquisition monitor onboard Himawari-8 for space environment monitoring on the Japanese meridian of geostationary orbit

“…Sandberg et al (2014) have examined the effective energies of GOES solar proton detectors using corrected interplanetary monitoring platform (IMP) 8 solar proton measurements. As shown by Rodriguez et al (2017), agreement is greatly improved between GOES and STEREO when using the effective energies estimated by Sandberg et al (2014). So, we also apply this effective energy of EPEAD in our analysis.…”