Submesoscale motions and their seasonality in the northern Bay of Bengal  

作　　者：Lanman Li Xuhua Cheng Zhiyou Jing Haijin Cao Tao Feng 

机构地区：[1]College of Oceanography,Hohai University,Nanjing 210098,China [2]Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519080,China [3]State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China

出　　处：《Acta Oceanologica Sinica》2022年第4期1-13,共13页海洋学报（英文版）

基　　金：The National Key R&D Program of China under contract No.2018YFA0605702;the National Natural Science Foundation of China under contract Nos 41876002 and 41776002。

摘　　要：The unbalanced submesoscale motions and their seasonality in the northern Bay of Bengal(BoB)are investigated using outputs of the high resolution regional oceanic modeling system.Submesoscale motions in the forms of filaments and eddies are present in the upper mixed layer during the whole annual cycle.Submesoscale motions show an obvious seasonality,in which they are active during the winter and spring but weak during the summer and fall.Their seasonality is associated with the mixed layer instability that depends on the mixed layer depth(MLD).During the winter,the MLD provides a much greater reservoir of the available potential energy,which promotes mixed layer instability to develop active submesoscale motions.The variations of MLD are likely modulated by the larger scale motions and the influxes of freshwater.Further investigations imply that the MLD and the stratified barrier layer are combined to determine the vertical structure of the submesoscale motions.The shallow MLD and strong stratification below during the summer and fall seem to prevent the downward extension of submesoscale motions.But in spring when the weak stratification exists,the penetration depth exceeds the base of the barrier layer.

关 键 词：submesoscale motions SEASONALITY northern BoB mixed layer instability STRATIFICATION 

分 类 号：P731.2[天文地球—海洋科学]