SST Changes in the Indian Sector of the Southern Ocean and Their Teleconnection With the Indian Monsoon During the Last Glacial Period

Abstract

The last glacial period was marked by interhemispheric coupling of abrupt climate changes in the northern and the southern high latitude regions through the “bipolar seesaw” mechanism. However, the spatial footprint of the bipolar seesaw in the mid-latitude Indian sector of the Southern Ocean and its likely transmission into the tropical region is not well understood. Here, we have reconstructed the first multi-centennial record of past SST variability in the Indian sector of the Southern Ocean spanning parts of MIS-3, the last deglaciation, and the early to mid-Holocene period using Mg/Ca of G. bulloides. We find that SST increased by around 4°C between the last glacial period and the early Holocene at the study site. Using this paleotemperature reconstruction and an independently available paleo-simulation, we show that the mid-latitude climate evolution in the Indian sector had signatures of both local-scale changes and those emanating from the coupled bipolar influence. We further show that most of the millennial variance in Indian monsoon records during the period was linked to mid-latitude SST variability in the Indian sector.