| Summary: | 碩士 === 國防大學理工學院 === 大氣科學碩士班 === 106 === At First, this study examins the quantitative and qualitative statistical rainfall characteristics by stages for 8 typhoons affecting Taiwan along the 4th track in the past 20 years. It is shown that the accumulated rainfall pattern significantly varies with respect to the relative locations of typhoon centers to Taiwan for different stages. The eastern regions, Kaohsiung, and Pingtung are areas where the total accumulated rainfalls are significant.
The microphysics scheme (MP) plays an important role for the rainfall simulation in a high resolution model. The WRF model is then used to simulate Typhoon Nepartak (2016) to compare the effects of six MPs on the track, intensity, and rainfall of the typhoon. These six MPs include one single-moment scheme [WRF Single-Moment 6-class scheme (WSM6)] and five double-moment schemes [WRF Double-Moment 6-class (WDM6), WRF Double-Moment 5-class (WDM5), Morrison, Thompson and Thompson Aerosol-Aware schemes]. The comparison has two folds: (1) between single- and double-moment schemes (WSM6 and WDM6); (2) among the other five double-moment schemes.
It is shown there is no obvious difference in the track and intensity of typhoon among simulations using different MPs, but the associated rainfalls have statistically significant difference. WDM6 scheme reveals a better performance on rainfall simulation for the comparison between single- and double-moment MPs. Morrison scheme results in the best similarity of rainfall to observations for the comparison of the 5 double-moment MPs. The average accumulated rainfalls of six schemes are all overpredicted. Comparing with the observation, the overprediction for WDM6 and WDM5 schemes are because of too much rainfall intensity, while for the others, the rainfall duration is too long.
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