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Modulation of El Niño events on summertime westward‐propagating wave patterns and tropical cyclone movement in the western North Pacific
Author(s) -
Ko KenChung,
Hong ChiCherng,
Liu JyunHong
Publication year - 2021
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.7079
Subject(s) - monsoon trough , trough (economics) , advection , tropical cyclone , climatology , barotropic fluid , geology , monsoon , subtropics , tropical wave , latitude , atmospheric sciences , physics , geodesy , fishery , biology , economics , macroeconomics , thermodynamics
This study investigated the association between westward‐propagating wave patterns and associated tropical cyclones (TCs), and eastern Pacific (EP) and central Pacific (CP) El Niño events. The wave pattern was more enhanced in the EP El Niño events than it was in the CP El Niño events, whereas the monsoon trough was deeper in the CP El Niño events than it was in the EP El Niño events. This enhanced monsoon trough together with the formation of a significantly stronger subtropical high strengthened the southeasterly flow, which caused TCs to detour northwestward to Japan in the CP El Niño events. An analysis of kinetic energy indicated that barotropic conversion provided more kinetic energy following the axis of the monsoon trough from the background flow to the westward‐propagating wave pattern in EP El Niño events, except near the centre of the monsoon trough where the background flow was more favourable for the wave pattern during CP El Niño events. The advection term by the southeasterly flow became more important in supporting the perturbation kinetic energy during CP El Niño events. Large‐scale circulation changes can influence smaller‐scale phenomena through barotropic conversion and advection.