Role of surface and sub-surface ocean parameters on cyclonic storms over Arabian Sea in the recent decades

The primary goal of the present paper is to examine variations in frequency and intensity of cyclonic storms over Arabian Sea using Accumulated cyclone energy (ACE) and Genesis Potential Index (GPI) from 1991-2020.For this purpose wavelet analysis is applied to surface and sub-surface ocean parameters viz Sea surface temperature (SST), Latent heat flux (LHF), Mixed layer depth (MLD), Depth of D26 Isotherm and Tropical cyclone heat potential (TCHP) to delve the probable changes. It is observed that the ACE signifies the intensity of tropical storms, has risen by 17.6% during the recent decade (2011-2020). LHF and SST are in phase with the intensification of cyclonic storms from Continuous wavelet transform (CWT) power spectrum analysis. Both SST and GPI were strongly correlated(0.8, 95% significant level) during pre-monsoon season.Siginifcant coherence was observed between frequency of cyclonic storms and TCHP in the recent decades through wavelet coherence transform technique. The cross wavelet transform (XWT) shows the frequency of cyclonic storms and SSTs are in phase during Indian Ocean dipole events. By these observations,this study helps in advance forecasting about formation and intensification of cyclonic storms over Arabian Sea.