The intrinsic nonlinear multiscale interactions among the mean flow, low frequency variability and mesoscale eddies in the Kuroshio region

作     者：Yang YANG X.San LIANG 

作者机构：School of Marine Sciences Nanjing University of Information Science and Technology School of Atmospheric Sciences Nanjing University of Information Science and Technology 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2019年第62卷第3期

页      面：595-608页

核心收录：

学科分类：07[理学] 

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 41806023 and 41276032) the National Program on Global Change and Air-Sea Interaction (Grant No. GASI-IPOVAI-06) the 2015 Jiangsu Program of Entrepreneurship and Innovation Group the Jiangsu Chair Professorship, the NUIST Startup Program (Grant No. 2017r054) the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province (Grant No. 18KJB170019) 

主　　题：Kuroshio Multiscale window transform Canonical transfer Multiscale energetics analysis Multiscale interaction Barotropic instability Baroclinic instability 

摘      要：Using a new functional analysis tool, multiscale window transform(MWT), and the MWT-based localized multiscale energetics analysis and canonical transfer theory, this study reconstructs the Kuroshio system on three scale windows, namely,the mean flow window, the interannual-scale(low-frequency) window, and the transient eddy window, and investigates the climatological characteristics of the intricate nonlinear interactions among these windows. Significant upscale energy transfer is observed east of Taiwan, where the mean Kuroshio current extracts kinetic energy from both the interannual and eddy *** is found that the canonical transfer from the interannual variability is an intrinsic source that drives the eddy activities in this region. The multiscale variabilities of the Kuroshio in the East China Sea(ECS) are mainly controlled by the interaction between the mean flow and the *** mean flow undergoes mixed instabilities(i.e., both barotropic and baroclinic instabilities) in the southern ECS, while it is barotropically stable but baroclinically unstable to the north. The multiscale interactions are found to be most intense south of Japan, where strong mixed instabilities occur; both the canonical transfers from the mean flow and the interannual scale are important mechanisms to fuel the eddies. It is also found that the interannual-scale energy mainly comes from the barotropically unstable jet, rather than the upscale energy transfer from the high frequency eddies.