Are ocean-moored buoys redundant for prediction of Indian monsoon?

Abstract

The Tropical Atmosphere Ocean (TAO) and Triangle Trans-Ocean Buoy Network (TRITON) buoys deployed in the tropical Pacific play a significant role in monitoring tropical Pacific conditions such as El-Nino/La-Nina in real-time. Earlier studies have illustrated the importance as well as irrelevance of moored buoy observations towards the prediction of sea surface temperature in the tropical Pacific Ocean. With the advent of Argo floats, have these moored buoy observations become redundant? In the present study, we address this question in the context of Indian summer monsoon rainfall (ISMR) prediction. The extreme monsoon year of 2018 was selected to test the above hypothesis. Without moored buoy observations being assimilated, the oceanic initial conditions and the seasonal forecasts had large oceanic temperature errors and forecasted a normal monsoon instead of a below-normal monsoon during 2018. Therefore, moored buoy observations are essential and should be assimilated to get realistic Pacific sea surface temperature (SST) and accurate ISMR predictions.