A Dynamical Linkage Between Western North Pacific Tropical Cyclones and Indian Monsoon Low-Pressure Systems

Abstract

The relatively weak tropical storms, known as low-pressure systems (LPSs), contribute as much as 60% of the seasonal precipitation over the hugely populated central India. More than a third of LPSs are formed by the downstream amplification of the westward propagating disturbances from the Pacific. Here, we show that the downstream LPS genesis is associated with the tropical cyclones (TCs) in the Western North Pacific (WNP). Four major clusters of landfalling TCs that have a relatively lesser degree of recurvature account for about 83% of the downstream LPS genesis. Causality in the fluctuations of the sea level pressure over the Bay of Bengal (BoB) prior to the initiation of LPSs is attributed to the Rossby wave activity over WNP through transfer entropy analysis. Our results suggest a potential for the prediction of the downstream synoptic activity over the BoB at least seven days ahead.