A possible relation between Arctic sea ice and late season Indian Summer Monsoon Rainfall extremes

Sourav Chatterjee,Nuncio Murukesh,Muthalagu Ravichandran,Roshin P Raj,Ola M Johannessen

doi:10.1038/s41612-021-00191-w

Sourav Chatterjee, Nuncio Murukesh + Show 3 more

Open Access

https://doi.org/10.1038/s41612-021-00191-w

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Abstract

The out-of-phase inter-decadal co-variability between summer (JJA) sea ice extent (SIE) in the Kara Sea (KS) sector of the Arctic Ocean and Indian Summer Monsoon Rainfall (ISMR) is found to be weakened during the recent decades with rapidly declining SIE in the KS (since the 1980s). However, SIE in the KS and frequency of ISMR extremes are found to have a consistent out-of-phase relation during the rapidly declining SIE periods. A possible physical mechanism for the relation between the late-season ISMR extremes and summer SIE in the KS is suggested, focusing on the recent years since the 1980s.

Highlights

The Indian Summer Monsoon Rainfall (ISMR) is the major source of drinking water to more than a billion people, owing to its roughly 70% contribution to the annual precipitation
It is further noted that the amount of sea ice concentration (SIC) variability in the Arctic due to the Rossby wave train generated from East Asian Summer monsoon and Indian Summer Monsoon together is comparable with the SIC variability induced by Arctic Oscillation[5]
It can be argued that the observed out-of-phase co-variability in sea ice extent (SIE) and ISMR during ETCW is mostly driven by the mid-latitude natural climate variabilities (e.g Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO)), whereas the differential response of those to anthropogenic forcing induced warming could possibly have affected the mid-latitude control on their relation

Summary

INTRODUCTION

The Indian Summer Monsoon Rainfall (ISMR) is the major source of drinking water to more than a billion people, owing to its roughly 70% contribution to the annual precipitation. The increasing frequency of extreme ISMR events[1,2], causing severe flooding and huge socio-economic challenges, demand adequate adaptation and mitigation strategies Understanding both the local driving factors and remote teleconnections of extreme ISMR events is key for better assessment and improved future projections of extreme ISMR events at different time scales. Since the beginning of the satellite records in 1979, the Arctic sea ice extent (SIE) has been consistently declining at a very alarming rate with the largest trend of 12.9 ± 2.2% per decade in September and about 4.4% per decade in annual mean[6] It is still unclear if this rapid sea ice decline can influence the tropical extremes, or in particular the extreme rainfall events during ISMR. A possible physical mechanism for the effect of SIE variability in the KS on ISMR extremes is proposed

RESULTS AND DISCUSSION

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