[M-GI29] Data assimilation: A fundamental approach in geosciences

[MGI29-12] Data assimilation of electron radiation belts using the Arase high energy electron data

★Invited Papers

*三好 由純¹、上野 玄太²、齊藤 慎司³、栗田 怜⁴、堀 智昭¹、今城 峻¹、三谷 烈史⁵、篠原 育⁵、高島 健⁵、東尾 奈々⁵ (1.名古屋大学宇宙地球環境研究所、2.統計数理研究所、3.情報通信研究機構、4.京都大学生存圏研究所、5.宇宙航空研究開発機構)

キーワード：放射線帯、あらせ衛星、粒子フィルター

Dynamical evolution of the outer belt electrons is determined by a delicate balance among several processes. To discriminate what physical processes are dominant for the large flux enhancement of the outer belt electrons, we have developed the data assimilation code on the outer belt electrons using the high energy electron data from Arase/XEP and HEP instruments. In this study, the particle filter and the particle smoother are used, which are effective for the non-linear/non-Gauss distribution problem. We include the radial diffusion coefficient, the lifetime due to the pitch angle scattering, and the internal source model as the state vector and estimate the dynamical variations of these parameters. From this assimilation, we derive the time variations of the diffusion coefficients and the wave amplitudes, which can be used for better modeling of the radiation belt electrons.