[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

*Yoshizumi Miyoshi¹, Genta Ueno², Shinji Saito³, Satoshi Kurita⁴, Tomoaki Hori¹, Shun Imajo¹, Takefumi Mitani⁵, Iku Shinohara⁵, Takeshi Takashima⁵, Nana Higashio⁵ (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.The Institute of Statistical Mathematics, 3.National Institute of Information and Communications Technology, 4.Research Institute for Sustainable Humanosphere, Kyoto University, 5.JAXA)

Keywords:radiation belts, Arase, Particle Filter

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.