The mechanism linking the variability of the Antarctic sea ice extent in the Indian Ocean sector to Indian summer monsoon rainfall

Abstract

The study investigates the mechanism of teleconnection between the variability of sea ice extent (SIE) in the Indian Ocean sector of the Southern Ocean and the variability of Indian summer monsoon rainfall. We utilized reanalysis, satellite, in-situ observation data, and model output from the coupled model intercomparison project phase 5 (CMIP5) from 1979 to 2013. The reanalysis data revealed that the Indian Ocean sector SIE during April-May-June (AMJ) significantly correlated with the Indian summer monsoon rainfall over Peninsular India. Changes in the SIE in the Indian Ocean sector excite meridional wave train responses along the Indian Ocean. Anomalous meridional circulations contribute to the strengthening (weakening) of the Polar, Ferrel, and Hadley cells, inducing strong (weak) convective activity over the Indian latitudes during high (low) sea ice phases. The strong (weak) convective activity over the Indian region leads to more (less) rainfall over the Indian region, mainly western Peninsular India, during high (low) sea ice phase years. Furthermore, a stronger (weaker) polar jet during the high (low) sea ice phase is also noted. The selected CMIP5 models captured certain atmospheric teleconnection features found in the reanalysis. During AMJ, the SIE simulated by the NorESM1-M model significantly positively correlated with Indian summer monsoon rainfall, whereas the IPSL-CM54-LR model showed a negative correlation.