2021 Fiscal Year Final Research Report
Development of a data assimilation method toward high-accuracy paleoclimate reconstruction
| Project/Area Number |
17K14397
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | Hirosaki University (2021)
Institute of Physical and Chemical Research (2017-2019) |
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Principal Investigator |
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| Project Period (FY) |
2021-03-01 – 2022-03-31
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| Keywords | データ同化 / 古気候復元 |
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| Outline of Final Research Achievements |
This study developed a method to reconstruct the last millennium climate with high accuracy compared to previous methods. The method proposed in this study merges climate model simulations and observations recorded in climate proxies with data assimilation. The special character of the proposed method is to estimate the initial conditions of the model and to conduct forecast with it. By doing so, the model simulation is constrained by assimilated observations and become closer to the realistic state.
The method was tested with simplified climate model named SPEEDY under the perfect model scenario.
The result showed that the climate reconstruction with the proposed method is better than the previous methods when the length of predictability is longer than the averaging time of the observations. Considering that the typical temporal resolution of the proxies and the predictability in the real world, we can expect that the proposed method improves the skill of paleoclimate reconstruction.
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| Free Research Field |
水同位体水文気候学、データ同化、数値天気予報
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| Academic Significance and Societal Importance of the Research Achievements |
長期の気候変動を描くことで、気候システムの変動メカニズムに対する理解を深め、深刻な影響が懸念される地球温暖化により良く備えることができると期待できる。一方、測器による観測が入手可能な期間はたかだか150年程度であり、気候システムの全容を捉えるには短すぎる。地学的な手がかりをもとに気候を復元する必要があるが、その手法には大きな不確実性が残されていた。本研究が提案する手法を用いることで、より正確な気候復元の実現が可能になる。
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