Space Weather impact on the degradation of NOAA POES MEPED proton detectors

TL;DR

This study investigates how space weather, specifically geomagnetic activity, influences the degradation of NOAA POES MEPED proton detectors, and develops a model to correct for this degradation based on radiation dose and geomagnetic indices.

Contribution

It introduces a model that accounts for space weather effects on detector degradation, improving calibration accuracy for NOAA POES MEPED instruments.

Findings

Degradation correlates with radiation dose and geomagnetic activity.

The model effectively estimates correction factors across multiple satellites.

Degradation rate is independent of spacecraft and detector orientation when considering space weather.

Abstract

The Medium Energy Proton and Electron Detector (MEPED) on board the National Oceanic and Atmospheric Administration Polar Orbiting Environmental Satellites (NOAA POES) is known to degrade with time. In recent years a lot of effort has been put into calibrating the degraded proton detectors. We make use of previous work and show that the degradation of the detectors can be attributed to the radiation dose of each individual instrument. However, the effectiveness of the radiation in degrading the detector is modulated when it is weighted by the mean $\textit{ap}$ index, increasing the degradation rate in periods with high geomagnetic activity, and decreasing it through periods of low activity. When taking $\textit{ap}$ and the radiation dose into account, we find that the degradation rate is independent of spacecraft and detector pointing direction. We have developed a model to estimate the correction factor for all the MEPED detectors as a function of accumulated corrected flux and the $\textit{ap}$ index. We apply the routine to NOAA POES spacecraft starting with NOAA-15, including the European satellites MetOp-02 and MetOp-01, and estimate correction factors.