日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

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-OS09] 海洋混合学:物質循環・気候・生態系の維持と長周期変動の解明

2019年5月26日(日) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:安田 一郎(東京大学大気海洋研究所)、日比谷 紀之(東京大学大学院理学系研究科地球惑星科学専攻)、西岡 純(北海道大学低温科学研究所)、伊藤 進一(東京大学大気海洋研究所)

[AOS09-P04] Mixing processes observed by a slocum glider at the Oyashio-TWC front

*長谷川 大介1田中 雄大1奥西 武1安田 一郎2 (1.国立研究開発法人 水産研究・教育機構 東北区水産研究所、2.東京大学 大気海洋研究所)

キーワード:二重拡散対流、混合、キャベリング

In order to grasp the detailed mixing processes along the frontal region between the Oyashio and the Tsugaru Warm Current (TWC), we conducted a zigzag survey crossing the front several times from the merging region of the two current systems to the down stream by an underwater glider (Slocum G2 Glider) equipped with a turbulence sensor, from July 24thto August 29thin 2017. The observed frontal structure indicated the subduction and the intrusion processes of the cold and fresh Oyashio water under the warm and salty TWC water, along layer between 26.5 to 26.8 sigma-theta, which resulted the favorable conditions to the salt finger convection at the upper interface along the 26.5 sigma-theta, and the diffusive convection at the lower interface along the 26.8 sigma-theta where the fresh and cold Oyashio water lying above the warm and salty water. The strong turbulence intensity is observed around the intruded layer, and the mean temperature and the salinity in the layer became warmer and saltier with the increase of the distance from the front, which suggested the time evolution of the vertical mixing driven by double diffusive convections between the three different water masses. Though the strongest turbulence intensity was observed around the frontal region, which may suggest the importance of the cabbeling effect as the additional source of the turbulent mixing.