Rainfall strength and area from landfalling tropical cyclones over the North Indian and western North Pacific oceans under increased CO2 conditions

Climate change due to greenhouse gases has fueled more intense tropical cyclones (TCs) globally. However, the characteristics rainfall strength (RS) and rainfall area (RA) of TCs and their future changes in regional scales are not yet fully understood. Here, using ultra-high-resolution coupled model simulations, we investigate the dominant factors which control rainfall characteristics of landfalling TCs in the North Indian Ocean (NIO) and western-North Pacific (WNP) and their future change in responses to doubling and quadrupling of atmospheric CO2 concentrations. In the NIO, RS increases more than RA when CO2 rises, but the WNP shows the opposite behavior. We demonstrate that RS is highly related to the lifetime maximum intensity, landfall intensity, and latent heat flux (LHFLX), while RA depends mainly on LHFLX, relative humidity at 600 hPa, and vertical wind shear over the WNP. Our results suggest the need to establish regional-scale adaptation strategies for future changes in landfalling TCs rainfall.

Automated summary

Climate change has resulted in more intense tropical cyclones globally, but the rainfall characteristics of these cyclones and their future changes at regional scales are not fully understood. In this study, using high-resolution model simulations, we investigate the factors that control the rainfall characteristics of landfalling tropical cyclones in the North Indian Ocean and western-North Pacific and their response to increasing atmospheric CO2 concentrations. Our results show that rainfall intensity and area behave differently in these regions, with rainfall intensity increasing more than area in the North Indian Ocean and the opposite in the western-North Pacific. We identify the key factors that influence rainfall intensity and area, highlighting the need for regional-scale adaptation strategies for future changes in landfalling tropical cyclones rainfall.