日本地球惑星科学連合2022年大会

講演情報

[E] 口頭発表

セッション記号 A (大気水圏科学) » A-OS 海洋科学・海洋環境

[A-OS12] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

2022年5月23日(月) 10:45 〜 12:15 201A (幕張メッセ国際会議場)

コンビーナ:伊藤 進一(東京大学大気海洋研究所)、コンビーナ:平田 貴文(北海道大学 北極域研究センター)、Hofmann Eileen E(Old Dominion University)、座長:平田 貴文(北海道大学 北極域研究センター)


11:15 〜 11:30

[AOS12-08] Dependence of horizontal characteristic scale of chlorophyll a distribution on eddy activity at the mid-latitudes of global oceans, and its long-term change

*金子 仁1伊藤 進一2、佐々木 建一1 (1.海洋研究開発機構、2.東京大学大気海洋研究所)

キーワード:クロロフィル a、海洋中規模渦、ロスビー波、西岸境界、内部変形半径、ラインズスケール

Understanding of the spatial distribution of near-surface oceanic chlorophyll a (Chl-a) in relation to eddy activity is important because Chl-a is critical to biological production and carbon absorption, and its distribution is closely related to meso-scale eddies and Rossby waves. Chl-a distributions based on satellite observations from 2001 to 2018 were analyzed in association with eddy activity in mid-latitude regions of the five ocean basins (North/South Pacific, North/South Atlantic, and South Indian oceans) and related to physical eddy scales including the internal Rossby deformation radius (LD) and Rhines scale (LR). In the open ocean, the horizontal scale of Chl-a (D) decreased with increasing eddy kinetic energy (EKE), converging to πLD in the high-eddy-activity region. The ratio of zonal (Dz) to meridional (Dm) scales, RD (= Dz/Dm), converged to 1 with increasing EKE, implying isotropic uniformization with meso-scale eddies. In regions of low EKE (especially the central subtropical and eastern parts of each basin), Dm was larger than LD, with a scale similar to πLR. In these regions, Dz values greater than Dm were found (with scales of 500–1000 km), indicating the effects of planetary phenomena on Chl-a. In such regions the sensitivity of D to EKE tended to be higher than in western boundary regions, indicating the influence of meso-scale eddy activity on the Chl-a distribution, even with low EKE. We will also show the decadal change in the scale of D in the presentation.