Seasonal Variations of Tropical Cyclone Genesis and Landfall Patterns Impacting Southeast Asia in a Warmer Climate

Evolving tropical cyclone characteristics are expected to amplify coastal hazards in a warmer climate. Here, we investigated seasonal-scale tropical cyclone genesis and landfall patterns from >64,000 statistically-downscaled tropical cyclones that impact Southeast Asian coastlines from the historical (1881-1900) through the future (2081-2100) eras for both moderate and high emission scenarios. From the historical to future eras, tropical cyclone genesis shifts northwards across seasons, with an increased likelihood of genesis adjacent to major coastlines. Proportional increases in genesis exceed 100% during the winter monsoon season and up to 50% during the summer monsoon season. Relative humidity and vertical wind shear become increasingly important influences on tropical cyclone genesis, particularly during the summer monsoon and autumn seasons. There are also increased likelihoods of tropical cyclones making their first landfall along the coastlines of the Philippines and Indonesia during the winter monsoon and spring seasons, and along mainland Southeast Asian coastlines during the summer monsoon and autumn seasons. These changes demonstrate the need for improved coastal resiliency and mitigation strategies in this highly populated part of the world.