The vertical structure of annual wave energy flux in the tropical Indian Ocean

Progress in Earth and Planetary Science

Tomomichi Ogata¹  Zimeng Li²  Hidenori Aiki³  Motoki Nagura⁴ 

[1] Application Laboratory, Japan Agency for Marine-Earth Science and Technology, Kanazawa-ku, 236-0001, Yokohama, Japan;Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, 464-8601, Nagoya, Japan;Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, 464-8601, Nagoya, Japan;Application Laboratory, Japan Agency for Marine-Earth Science and Technology, Kanazawa-ku, 236-0001, Yokohama, Japan;Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 237-0061, Yokosuka, Japan;

关键词: Indian Ocean;    Kelvin wave;    Rossby wave;    Seasonal variation;    Vertical structure;    Wave energy;   

DOI  :  10.1186/s40645-021-00432-9

来源: Springer

【 摘 要 】

A recently developed energy flux diagnosis scheme, which incorporates a smooth connection between the tropical and subtropical zones, is used in the present study to investigate vertically propagating waves in the tropical Indian Ocean (IO) based on the result of a linear, continuously stratified ocean model driven by climatological wind forcing. This extended diagnosis reveals deep-reaching eastward energy fluxes at the equator which develop four times per year and are associated with equatorial Kelvin waves (KWs) generated by semiannual winds. The authors find that the downward transfer of wave energy is particularly deep in the southern Bay of Bengal (SBoB). This downward flux is attributed to off-equatorial Rossby waves and appears four times per year, maximizing its amplitude during November–December. Southwesterly winds in the Arabian Sea intensify eastward energy flux of KWs at mid-depth, which maximizes in amplitude in August. This is contrastive to KW energy flux at the surface which peaks in May. These mid-depth equatorial KW packets subsequently arrive at the eastern boundary of the IO and are diffracted poleward to produce downward energy flux in November and December detected in the SBoB.

【 授权许可】

CC BY