| dc.description.abstract | In the past few decades, extremely severe rainfall events have become more frequent and intense. Most of them are due to the afternoon thunderstorms in summer. Afternoon thunderstorm causes floods and landslides, which not only hurts the sociality of humans, but also the biosphere. Hence, the most important topic is to understand the detail of rainfall changes in the future.
In this study, WRF model will be used to simulate the long-term projection of precipitation. First, we divide the 21st Century into four parts, which are 2011-2015, 2046-2050, 2071-2075 and 2096-2100. By using CMIP5 under RCP8.5 scenario, a standard of changes of the weather conditions, we utilize GFDL model’s results as WRF input. The results show that the intensity of the afternoon thunderstorm in Taipei will increase. There are five main reasons that cause changes in afternoon thunderstorm: (1) Stronger southwesterly, (2) stronger sea breeze from Tamsui River, (3) stronger convergence in the daytime in Taipei basin, (4) higher mixing ratio at 850hPa, (5) higher equivalent potential temperature from surface to 500hPa. The difference between the present and the future will become larger as time approaches the end of the 21st century.
Furthermore, the strongest 10% afternoon thunderstorm cases have been selected. After rearranging all the cases sorted by rainfall amount, we find out that the median will increase by 25% and the rainfall of the most extreme case will double. The extreme afternoon thunderstorm rainfall will become more intense in the future.
To sum up, this study mainly focuses on the difference between thunderstorm days in the future and in the present. The change in dynamic conditions, thermal conditions, and water vapor can lead to the intensity change of the afternoon thunderstorms over Taipei basin in the future.
| en_US |