碩士 / 國立臺灣大學 / 大氣科學研究所 / 106 / Locations of outer rainbands and the embedded convective activities can affect tropical cyclone (TC) size, and it has been suggested that the secondary circulation induced by the rainbands can affect the momentum transport in the lower level, and more momentum import in the lower level leads to the expansion of TC. In addition, removing surface heat fluxes weakens the rainband activities. Therefore, this study attempts to further understand the impact of surface heat fluxes on TC size and how do surface heat fluxes in different area affect TC size.
The Advanced Research Weather Research and Forecasting (ARW-WRF) model (version 3.5.1) is used in this study to conduct simulations of Typhoon Megi (2016). Several experiments are carried out, including a control (CTL) simulation and sensitivity experiments with surface heat fluxes suppressed in varying degrees and in inner and outer core of TC. The results show that more surface heat fluxes leads to a larger TC. Furthermore, outer core surface heat fluxes are more sensitive to TC size than inner core surface heat fluxes. Suppressing surface heat fluxes weakens the rainbands around the suppressed area. The weakened rainbands slow down the secondary circulation. However, the weakening of secondary circulation resulted from the weakened inner rainbands is constrained in the inner core region, so it only slightly affects the absolute angular momentum import in the outer region. On the other hand, inactive outer rainbands leads to a broader secondary circulation weakening, so the absolute momentum import in the outer region is less, which is not favorable for TC size increase. Therefore, the supplementation of surface heat fluxes in the outer core region is more important than that in the inner core region.
| Identifer | oai:union.ndltd.org:TW/106NTU05022019 |
| Date | January 2018 |
| Creators | Li-Zhi Shen, 沈里治 |
| Contributors | Chun-Chieh Wu, 吳俊傑 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 69 |
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