Modeling the Relationship of ≥2 MeV Electron Fluxes at Different Longitudes in Geostationary Orbit by the Machine Learning Method

Abstract

The energetic electrons in the Earth’s radiation belt, known as “killer electrons”, are one of the crucial factors for the safety of geostationary satellites. Geostationary satellites at different longitudes encounter different energetic electron environments. However, organizations of space weather prediction usually only display the real-time ≥2 MeV electron fluxes and the predictions of ≥2 MeV electron fluxes or daily fluences within the next 1–3 days by models at one location in GEO orbit. In this study, the relationship of ≥2 MeV electron fluxes at different longitudes is investigated based on observations from GOES satellites, and the relevant models are developed. Based on the observations from GOES-10 and GOES-12 after calibration verification, the ratios of the ≥2 MeV electron daily fluences at 135° W to those at 75° W are mainly in the range from 1.0 to 4.0, with an average of 1.92. The models with various combinations of two or three input parameters are developed by the fully connected neural network for the relationship between ≥2 MeV electron fluxes at 135° W and 75° W in GEO orbit. According to the prediction efficiency (PE), the model only using log10 (fluxes) and MLT from GOES-10 (135° W), whose PE can reach 0.920, has the best performance to predict ≥2 MeV electron fluxes at the locations of GOES-12 (75° W). Its PE is larger than that (0.882) of the linear model using log10 (fluxes four hours ahead) from GOES-10 (135° W). We also develop models for the relationship between ≥2 MeV electron fluxes at 75° W and at variable longitudes between 95.8° W and 114.9° W in GEO orbit by the fully connected neural network. The PE values of these models are larger than 0.90. These models realize the predictions of ≥2 MeV electron fluxes at arbitrary longitude between 95.8° W and 114.9° W in GEO orbit.

Prediction Models of ≥2 MeV Electron Daily Fluences for 3 Days at GEO Orbit Using a Long Short-Term Memory Network

“…Sun et al [47] showed GOES satellites are mostly around 135 • W or 75 • W, and ≥2 MeV electron daily fluences between 135 • W and 75 • W are different. In this study, the ≥2 MeV electron daily fluences at a 1 min resolution from GOES-08 and GOES-12 satellites at roughly 75 • W between 1995 and 2010, and from GOES-10 and GOES-11 satellites at about 135 • W between 1999 and 2010 are used.…”

“…The different ≥2 MeV electron daily fluences at different longitudes in GEO orbit has been researched, such as Ling et al [36], Shin et al [37], Onsager et al [45], Sun et al [46] and Sun et al [47]. Sun et al [47] reported that the ratios of ≥2 MeV electron daily fluences (cm −2 •sr −1 •day −1 ) from GOES-10 at about 135 • W to those from GOES-12 at about 75 • W are mainly in the range of 1.0 to 4.0, with an average of 1.92.…”

“…The different ≥2 MeV electron daily fluences at different longitudes in GEO orbit has been researched, such as Ling et al [36], Shin et al [37], Onsager et al [45], Sun et al [46] and Sun et al [47]. Sun et al [47] reported that the ratios of ≥2 MeV electron daily fluences (cm −2 •sr −1 •day −1 ) from GOES-10 at about 135 • W to those from GOES-12 at about 75 • W are mainly in the range of 1.0 to 4.0, with an average of 1.92. With the assumption that the solar wind and geomagnetic disturbance conditions are stable and unchanged, Sun et al [46] calculated ≥2 MeV electron daily fluences at different longitudes in GEO orbit on the same day based on the AE8+IGRF+T96 model.…”

“…The minimum and maximum values of ≥2 MeV electron fluences of the GEO satellites on every day of the year appear near 70 • W and 170 • W, respectively, with their ratios varying from 1.86 to 2.13 per year. According to Sun et al [47], the ratios of ≥2 MeV electron daily fluences at 135 • W and 75 • W per year range from 1.63 to 1.79, with an average ratio of 1.71. The differences between ≥2 MeV electron daily fluences at different longitudes in GEO orbit are primarily influenced by magnetic latitudes [45,46].…”

Prediction of Radiation Belts Electron Fluxes at a Low Earth Orbit Using Neural Networks With PROBA‐V/EPT Data

“…Many works have arisen these last two decades where the satellite measurements in the inner magnetosphere have been used to figure out radiation belt dynamics and, more recently, to train machine learning models. The Geostationary Operational Environmental Satellite network with its fleet of geosynchronous equatorial orbit (GEO) satellites launched since the seventies (https://www.nasa.gov/content/goes) have been extensively employed for such goal (see e.g., Landis et al., 2022; Myagkova et al., 2019; Son et al., 2022; Sun et al., 2021; Wei et al., 2018). The launch of Radiation Belt Storm Probes (RBSP) in 2012 in a Low‐Medium Earth orbit with a highly elliptic equatorial trajectory (Mauk et al., 2012), later renamed Van Allen Probes, has enormously contributed to the research on the physical processes governing the radiation belts and revamped our knowledge of the near‐Earth space by demonstrating, for example, the existence of a third ultra‐relativistic radiation belt (Mann et al., 2016) during high geomagnetic activity.…”