Role of Tropical Cyclone Heat Potential In Intensification of Tropical Cyclones in The North Indian Ocean

Abstract

Tropical Cyclones (TCs) form over the warm tropical ocean, deriving energy from the upper layer of the ocean under suitable atmospheric conditions. Recent advances in numerical weather prediction has led to significant improvement in TC track forecasting, however intensity forecast still remains a challenge. The poor intensity skill of the models is partly attributed to the inadequate representation of the upper ocean. Only sea surface temperature (SST), a skin-layer property is used in most of the models as the input from oceans. Therefore, understanding the impact of sub-surface ocean parameters in modulating TC intensity is of paramount importance. It becomes even more important over a basin such as the North Indian Ocean (NIO), known for its unique subsurface dynamics. The present study investigates the role of oceanic surface and subsurface features like SST, Sea Level Anomaly (SLA), TC Heat Potential (TCHP) and underlying eddies in the genesis and intensification of TCs in the NIO. newlineThe study primarily covers a period from 2001 to 2018, consisting of 72 storms both in the Arabian Sea (AS) and Bay of Bengal (BoB) basins of the NIO utilizing cyclones intensity (CI) data from archived best tracks. Before analysing the association of TCHP and CI, a comparative study of available TCHP products from model (Indian National Centre for Ocean Information-Global Ocean Data Assimilation System (INCOIS-GODAS)) and satellites (Artificial Neural Network technique generated TCHP from National Remote Sensing Centre, two-layer reduced gravity model (TLGM) derived delayed time and near real-time TCHP from National Oceanic and Atmospheric Administration) with those from in situ moored buoy and Argo observations are performed. The limited period INCOIS-GODAS model TCHP had the best match with in situ followed by TLGM delayed time, ANN-based and TLGM near real time TCHP products. Similar analysis during TCs.