Effect of Increasing Surface Air Temperature and Sea Surface Temperature on Typhoon Rainfall Maximization

18:00 Tuesday 28 May




Jeonghyeon Choi (Korea, Republic of) 1; Kyungmin Kim (Korea, Republic of) 1; Inkyeong Sim (Korea, Republic of) 1; Jeongeun Won (Korea, Republic of) 1; Okjeong Lee (Korea, Republic of) 1; Sangdan Kim (Korea, Republic of) 2

1 - Division of Earth Environmental System Science (Major of Environmental Engineering), Pukyong National University, Busan, South Korea; 2 - Department of Environmental Engineering, Pukyong National University, Busan, South Korea

The increase in typhoon intensity to the East Asia is one of the effects of climate change. The increase in surface air temperature (SAT) and sea surface temperature (SST) due to global warming increases the intensity of typhoon rainfall. The rise of the SAT increases the amount of saturated water vapor in the atmosphere, which improves the ability of the typhoon to retain moisture, and an increase in SST increases the amount of total energy supplied to the typhoon. Therefore, it is necessary to anticipate and prepare for the increase of typhoon rainfall due to climate change. In this study, typhoon rainfall maximization was carried out based on Typhoon Maemi which suffered great damage to Korea in 2003.

To do this, we maximized typhoon rainfall by increasing SAT and SST using Weather Research and Forecasting model (WRF), and analyzed the effect of increasing SAT and SST on typhoon rainfall. We calculated the maximized rainfall depth (MR) in the SAT and SST increase scenarios and compared it with the existing probable maximum precipitation (PMP). Finally, the increase of the SAT and SST to maximize the typhoon rainfall was selected. In the numerical simulations, SAT and SST were constantly increased from 0ºC to 4.5ºC at intervals of 0.5ºC. As the SAT and SST increase, the overall typhoon rainfall also increased. However, the inland rainfall did not necessarily increase due to the spatial distribution of rainfall. Therefore, in order to estimate the MR of a specific region through the typhoon rainfall maximization method proposed in this study, it is necessary to examine a reasonable SAT and SST increase rather than an unconditional increase of SAT and SST. As a result of estimating the MR for various durations of the Busan Metropolitan City (BMC) of Korea, which is the main damage area of Typhoon Maemi, it is shown that when the SAT and SST are increased by 3.0ºC and 3.5ºC respectively, the largest MR occurs in BMC.

The duration 12-hour MR is 957.5 mm, which is about 30% higher than the current PMP (726.7 mm). These numerical simulation methods are expected to be useful for designing drainage structures that reflect the impacts of climate change and for preparing evacuation plans for disaster scenarios.

Acknowledgement: This work is supported by the Korea Environmental Industry & Technology Institute (KEITI) grant funded by the Ministry of Environment (RE201901073).