Deterministic and probabilistic forecasting of the >2 MeV flux at GEO using geomagnetic and solar wind parameters.

Abstract:

The dynamics of the near-relativistic electrons at GEO are commonly used as the boundary conditions for empirical and physics-based models of the radiation belts. The >2 MeV fluxes can vary by over four orders of magnitude on timescales varying from several minutes to months. Ultimately, this variability is driven by the solar wind, but the interaction between the solar wind and the magnetosphere introduces a complicating factor. Using six years-worth of data from GOES15, we examine how well geomagnetic indices and solar wind parameters can predict the likelihood that the >2 MeV flux will exceed either 1000 or 10000 pfu in windows extending up to 10 days into the future based on the amount of time that these parameters were above or below set thresholds. These forecasts were optimised and verified using their ROC and Peirce scores and Brier Skill Scores. Overall, we found that AL could provide the best forecasts using 4-6 days-worth of input data, with Brier Skill Scores of 0.12-0.32, closely followed by SYM-H and solar wind velocity. Although further optimisation may be possible by determining the forecasting parameters on a yearly basis, our methodology can provide skilful probabilistic and deterministic forecasts of the outer edge of the radiation belts.