Understanding the characteristics of rapid intensity changes of Tropical Cyclones over North Indian Ocean

Abstract

North Indian Ocean (NIO), which comprises of Bay of Bengal (BoB) and Arabian Sea (AS) basins, is one of the highly potential regions for Tropical Cyclones (TCs) in the world. Significant improvements have been achieved in the prediction of the movement of TCs, since the last decade. However, the prediction of sudden intensity changes becomes a challenging task for the research and operational meteorologists. Hence, the present study focuses on finding the climatological characteristics of such intensity changes over NIO regions. Rapid Intensification (RI) is defined as the 24-h maximum sustained surface wind speed rate equal to 30 knots (15.4 ms−1). The results suggest that the TCs formed over the NIO basin are both seasonal and basin sensitive. Since 2000, a significant trend is observed in RI TCs over the basin. At least one among three cyclones getting intensified is of RI category. More number of RI cases have been identified in the BoB basin than the AS. The post-monsoon season holds more RI and rapid decay cases, with 63% and 90% contribution. Most of the TCs are attaining RI onset in their initial stage. Further, India is receiving more landfalling RI TCs, followed by Bangladesh and Oman. The east coast of India, Tamil Nadu, and Andhra Pradesh are the most vulnerable states to these RI TCs. The cyclogenesis locations associated with RI cases hold higher moisture, and sea surface temperature as compared to the Non-RI cases.

Understanding the characteristics of microphysical processes in the rapid intensity changes of tropical cyclones over the Bay of Bengal

“…Note that the intensity bias is less when the model is initialized at a stronger stage of TCs. These results are consistent with earlier studies (Osuri et al ., 2013; Nadimpalli et al ., 2021; and cross‐references).…”

“…This includes large-scale processes such as wind shear, intrusion of dry air, oceanic conditions, and distance from the formation to the coast (Kaplan et al, 2010(Kaplan et al, , 2015 to the inner-core interactions related to MP, convective, and boundary layer processes (Liu et al, 2017;Zhang, 2018;Zhao et al, 2020). The North Indian Ocean (NIO) basin has experienced rapid intensity (RI) changes of TCs in recent years (Nadimpalli et al, 2021;Vinodhkumar et al, 2021). The studies over the NIO region have mainly focused on the impact of large-scale processes on the RI of TCs.…”

On occurrence of rapid intensification and rainfall changes in tropical cyclones over the North Indian Ocean

“…A recent study by Nadimpalli et al . (2021) reported that higher moisture and SST could be one of the reasons for the occurrence of more RI‐TCs during post‐monsoon as compared to the pre‐monsoon season. Balaguru et al .…”

Simulated dynamics and thermodynamics processes leading to the rapid intensification of rare tropical cyclones over the North Indian Oceans

“…However, improvement in forecasting skills for TC intensity still remains challenging (Wang and Chan 2002;DeMaria et al 2014). The operational intensity forecast error for the intense TCs (wind speed [48 knots) is considerably large over the NIO region (Nadimpalli et al 2021). To improve the forecasting skill of TC intensity, understanding the dynamics of TC intensiBcation is essential.…”