[A-CG30] 中緯度大気海洋相互作用

[ACG30-12] Observation of Maritime Water Vapor by Shipboard Microwave Radiometer

*吉田 聡¹、小松 幸生²、立花 義裕³、藤田 実季子⁴、山本 雄平⁵、川合 義美⁴、勝俣 昌己⁴、植原 量行⁶、箕輪 昌裕⁷、髙島 裕弥⁷ (1.京都大学防災研究所、2.東京大学大学院新領域創成科学研究科、3.三重大学、4.海洋研究開発機構、5.千葉大学、6.東海大学、7.古野電気株式会社)

キーワード：水蒸気、マイクロ波放射計、大気海洋相互作用、船舶観測

Maritime water vapor is important to understand atmosphere-ocean interaction and predict precipitation. However, the vertical profile and minute-scale variation are not clear because of observational difficulty. Although ground-mounted microwave radiometers (MWR) can observe vertical profiles of water vapor above with every few minutes, it is too large to set on ships. Recently, a small MWR, which is easily set on ships, has been developed. We have been observing maritime water vapor using the shipboard MWR since August 2020 to understand maritime water vapor distribution. Two ships, the training vessel (T/V) Seisui-maru of Mie University and the research and training vessel Bosei-maru of Tokai University have observed whole year, and four ships, research vessel (R/V) Hakuho-maru and R/V Shinsei-maru of the University of Tokyo, Mirai of Japan Agency for Marine-Earth Science and Technology, Koyo-maru of National Fisheries University, have observed in their training and/or research cruises. In result, water vapor vertical profiles from tropics to Arctic in Pacific region have been observed (Fig. 1). Sonde observations have been conducted in the several research cruses. The vertical profiles observed by MWR well match with the sonde observation under 5000 m altitude and capture fine-scale water vapor structure due to high-frequent observation over ocean, which has never been observed by sonde. For example, in July 2022, R/V Shinsei-maru observed water vapor profiles crossing the Kuroshio in the East China Sea. Water vapor increase over warm Kuroshio, and its thickness is shallower in upstream than downstream of air flow. The results show that Kuroshio supplies moisture to air mass from south, which will be an origin of precipitation downstream.