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

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

*中野 慎也¹、南 拓人²、高橋 太³、松島 政貴⁴、藤 浩明⁵、清水 久芳² (1.情報・システム研究機構　統計数理研究所、2.東京大学地震研究所、3.九州大学大学院理学研究院、4.東京工業大学理学院、5.京都大学大学院理学研究科附属地磁気世界資料解析センター)

キーワード：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.