日本地球惑星科学連合2025年大会

講演情報

[E] 口頭発表

セッション記号 M (領域外・複数領域) » M-GI 地球科学一般・情報地球科学

[M-GI26] Data assimilation: A fundamental approach in geosciences

2025年5月30日(金) 09:00 〜 10:30 展示場特設会場 (6) (幕張メッセ国際展示場 7・8ホール)

コンビーナ:中野 慎也(情報・システム研究機構 統計数理研究所)、堀田 大介(気象研究所)、大石 俊(理化学研究所 計算科学研究センター)、加納 将行(東北大学理学研究科)、座長:中野 慎也(情報・システム研究機構 統計数理研究所)、近藤 圭一(気象庁気象研究所)

09:45 〜 10:00

[MGI26-04] Ultra-High Spatiotemporal Resolution Reconstruction of the Climate around Japan with Large Ensemble of Climate Simulations and Old Documents

*岡崎 淳史1、渡部 哲史2、伊藤 幸司1,2、田尻 義了2 (1.千葉大学、2.九州大学)

キーワード:データ同化、古日記、d4PDF、粒子フィルタ

Many of the old documents in Japan, whether it be private or public, contain the records of weather types (e.g., sunny, cloudy, rainy) on a daily basis. Previous studies have used such records to reconstruct monthly to seasonal mean climate at the point where the document was written. Only a few studies reconstructed point-wise climate on a daily scale due to the difficulty of using such qualitative data. Climate field reconstructions with old documents are also limited.

This study proposes a data assimilation-based approach to use such data effectively for daily weather field reconstruction. We use the particle filter and a pre-existing large ensemble climate simulation known as d4PDF as a model prior ensemble. The d4PDF provides simulations that are longer than 3000 years with horizontal resolution of 20 km and enables ultra-high resolution climate reconstruction in the field of paleoclimate.

In the presentation, we show the feasibility of the approach for the present climate using AMeDAS data. We found that the prosed method reconstructs daily precipitation fields successfully. The reconstruction skill is robust to the number of observations to some extent, suggesting the feasibility of the weather reconstruction with actual weather daily data.