[M-GI30] Data assimilation: A fundamental approach in geosciences

[MGI30-11] A pilot study of geomagnetic data assimilation into a geodynamo model

*Shin ya Nakano¹, Takuto Minami², Futoshi Takahashi³, Masaki Matsushima⁴, Hiroaki TOH⁵, Hisayoshi Shimizu² (1.The Institute of Statistical Mathematics, 2.Earthquake Research Institute, the University of Tokyo, 3.Faculty of Science, Kyushu University, 4.School of Science, Tokyo Institute of Technology, 5.Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University)

Keywords:ensemble-based data assimilation, geodynamo model, secular variation

Geomagnetic secular variation is a long-term variation of the Earth's magnetic field. The magnetic field of the Earth is originated from a dynamo in the outer core. Modeling of geodynamo process is thus a straightforward approach for predicting geomagnetic secular variations. However, it is intrinsically difficult to resolve the current state of the geodynamo from observable magnetic field and to predict future evolution of geodynamo. We are developing a framework for estimating the current state of the geodynamo by using a data assimilation approach. As a preliminary study, we performed data assimilation experiments using synthetic geomagnetic data in order to evaluate if data assimilation methods are effective for estimating the state of the geodynamo. Some data assimilation schemes based on ensemble-based variational method were applied and compared. Preliminary results of the experiments will be demonstrated.