[A-CG52] 北極域の科学

[ACG52-15] The JAMSTEC Arctic regional Reanalysis system (JAMSTARs)

*鈴木 和良¹、Zupanski Milija²、段 卓志¹、Fassnacht Steven²、朴 昊澤¹、小林 秀樹¹、檜山 哲哉³ (1.国立研究開発法人海洋研究開発機構、2.コロラド州立大学、3.名古屋大学宇宙地球環境研究所)

キーワード：再解析、データ同化、積雪、北極環境

The JAMSTEC Arctic Regional reanalysis system (JAMSTARs) is a regional reanalysis framework based on 32 ensemble simulations covering areas from the Arctic to mid-latitudes. It routinely assimilates observational data from the US National Centers for Environmental Prediction (NCEP) PREPBUFR. The system provides tools to evaluate the impact of advanced land surface model parameterization and satellite retrieval on reanalysis accuracy. Its accuracy was assessed by comparing JAMSTARs with the ERA5 global reanalysis, MODIS snow cover, the US Climate Reference Network (USCRN), and US Snowpack Telemetry (SNOTEL) datasets. The results show that JAMSTARs achieves accuracy comparable to ERA5 for temperature, while it outperforms ERA5 in representing snowpack characteristics, such as snow depth. When assimilating AMSR2 Sea Surface Wind (SSW) data, the accuracy in polar regions improves, likely because the AMSR2 SSW data enhances the polar water cycle. In addition, a more sophisticated land surface model contributed to better surface reanalysis, especially regarding wind fields. The JAMSTARs system we developed can contribute to understanding extreme weather and permafrost changes in the Arctic and mid-latitudes, as well as provide a means to evaluate the impact of various observational data and land surface schemes. Eventually, this system is expected to serve as a tool for detailed monitoring of the rapidly changing Arctic environment, paving the way for the operation of Arctic Ocean routes and the utilization of related data.