Frequency and Intensity of Cyclonic Systems in CORDEX RCMs Model Environment under the Future Emission Scenarios

Abstract

Tropical Cyclonic Disturbances (TCDs) are one of the most extreme meteorological calamities bringing destruction to life and livelihood in the coastal societies across the globe. With the rising concerns of climate change today, addressing the TCDs in future scenarios under the representative concentration pathways (RCPs) in climate models becomes a necessity. The current study investigates the frequency and intensity of these cyclonic systems in future climate over the Bay of Bengal (BoB) which is one of most vulnerable regions on earth for deadliest TCDs. To assess the TCDs frequency and intensity, we have considered TCDs in regional climate model REMO2009 and RegCM4 in future climatic conditions. The future climatic conditions include the intermediate emissions (IE) represented as RCP4.5 (R4.5) and high emission (HE) pathways i.e., RCP8.5 (R8.5). For this, we have considered the upcoming decades 2031-2060 (as near future climate) at model horizontal resolution 0.44°x0.44° (spatial resolution ~ 50 km) under both RCPs in both models i.e., REMO2009 under R4.5, RegCM4 under R4.5, REMO2009 under R8.5 and RegCM4 under R8.5. The projected TCD frequencies in the models under both the RCPs show high occurrence frequencies. Further, we observe a bimodal characteristic in the occurrence with October as primary TCD active month and May as secondary in almost all conditions. However, highly intense TCDs are more dominant in the month of May. The projected TCDs in future emissions scenarios likely show slightly increased TCDs besides surge in the intensity. The current results possibly suggest more potential destructive impacts due to TCDs on the coastal societies lying beside the BoB in upcoming decades. Thus, the present study is likely to help in framing TCDs associated mitigation and adaptation policies by the apex decision making authorities.