Continual tropical cyclone and extreme urban heat (TC-Heat) compound events under East Asian metropolitan cities’ footprint

The development of megacities and irreversible trends in global warming have brought us new hazards through compound extreme weather events in the urban society. Extreme hot days are occasionally observed with subsidence and stagnant air conditions driven by far-distance approaching tropical cyclones. Instead of the cross-boundary poor air quality during the stagnant days, urban heat can also be potentially advected with a long-range air-mass transport under the tropical cyclone and extreme heat compound (TC-heat) events. Our previous study had suggested the peripheral circulation of distant TC located at 500-1250 km from Hong Kong may drive the downwind heating footprint from inland China to coastal cities. By integrating the gridded data from newly developed Japanese Reanalysis for Three Quarters of a Century (JRA-3Q) and ERA5-Land reanalysis dataset, this study aims to further explore the decadal variation in TC activities over the East-Asia domain (China, Japan, and Korea) under climate change, also to explore the patterns of 95^th percentile extremes in TC peripheral subsidence warming from 1990s, 2000s to 2010s, and the amplification of extreme TC-Heat risks with Wet-bulb globe temperature (WBGT) thermal indices in urbanized areas. Probabilistic TC-Heat risk maps were generated to indicate the potential “hotspots” for different cities when TC are located at different assessment grids. The risk maps can provide heat adaptation and resilience recommendations on the heat threat vulnerable groups in different countries and cities to safeguard their citizens from experiencing extreme heat mortality in our future cities.