The Life Cycle of Annual Waves in the Indian Ocean as Identified by Seamless Diagnosis of the Energy Flux

Abstract In previous studies, the role of large‐scale waves in tropical‐extratropical interactions has been little investigated in terms of wave energy transfer owing to the lack of appropriate diagnostic techniques. Using a new seamless scheme, the present study identifies a series of well‐defined horizontal circulation routes of wave energy in the Indian Ocean on an annual basis. One of these features represents a localized cyclonic circulation close to the western boundary in each hemisphere while the other manifests as a basin‐scale cyclonic circulation in the eastern Indian Ocean. For the second baroclinic mode, eastward energy fluxes associated with equatorial Kelvin waves appear when zonal velocity anomaly exhibits eastward and westward peaks (four times per year) in response to the monsoon‐wind cycle. Identification of these key pathways of wave energy circulation enables us to better understand how waves in the tropical and subtropical regions interconnect at the zonal boundaries of the Indian Ocean.