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Enhanced Intraseasonal Variability of the Upper Layers in the Southern Bay of Bengal During the Summer 2016
Author(s) -
Huang Huaming,
Wang Dongxiao,
Yang Lei,
Huang Ke
Publication year - 2021
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2021jc017459
Subject(s) - baroclinity , bay , rossby wave , geology , climatology , anomaly (physics) , barotropic fluid , bengal , instability , monsoon , oceanography , mooring , atmospheric sciences , physics , mechanics , condensed matter physics
Intraseasonal variability (ISV) of the upper 500 m circulation in the southern Bay of Bengal (SBOB) is investigated by using mooring observations and analyzing model outputs. An enhanced ISV is found in the upper 500 m currents during summer 2016. In summer 2016, a boreal summer intraseasonal oscillation (BSISO) propagated northward in tropical Indian Ocean. The intraseasonal easterly anomaly associated with the BSISO forces the equatorial wave to propagate into SBOB, driving the ISV of the upper currents. However, the analysis shows that the enhancement of ISV may be more related to the oceanic instability. During summer 2016, the intensity of the southwest monsoon current (SMC) significantly increased with the position of the flow axis closer to the SBOB's eastern boundary. Energy analysis reveals that the SMC could strengthen the westward propagating Rossby wave through baroclinic and barotropic instability, which can lead to the enhanced ISV of the upper currents in SBOB.