碩士 / 國立中央大學 / 大氣物理研究所 / 101 / Double eyewall(or concentric eyewall) structure, often appears in strong tropical cyclones. As the strong intensity and the dramatic structure changes they have, to study their physical feature and to improve the accuracy of forecast are very important for coastal area.
Observation data is needed in order to verify the hypothesis raised from model experiments which are created to study double eyewall cyclones. In addition, simply analyzing a great amount of observation data (Sitkowski et al. 2011) can also give us understanding of their structure and intensity changes.
Unlike Atlantic, there is no regular flight observations in West north Pacific. Instead, researchers use satellite-retrieved information as database. However, passive microwave observations are temporal discontinuously in tropical cyclone monitoring.
Fortunately, Ushio et al.（2009）applied Kalman filter to combine infrared and passive microwave data to estimate the hourly precipitation rate, named as Global Satellite Mapping of Precipitation(GSMaP). The development of GSMaP provide possibility to analyze West north Pacific's double eyewall typhoons temporal continuously as Atlantic's.
In this work, hourly GSMaP imageries were divided into 12 sections, and we identified the locations of inner and outer eyewall at each time from the locations of local maximum precipitation in each section, and resolved the precipitation intensity of each eyewall. As the results, the structure and intensity changes of 21 double eyewall cases were recorded, and classified into 2 types: replacement type and non-replacement type. replacement(non-replacement) cases have much(less) significant replacement feature when outer eyewall contracts, and their outer eyewall forms with larger(smaller) radius and replacement takes less(longer) time to be completed, which supports Didlake and Houze (2011)'s theory. The result is compared with previous papers, which have been analyze double eyewall structures through observation data but from different platforms, and the similar eyewall repalcement time and relative eyewall size were found in this study.
| Identifer | oai:union.ndltd.org:TW/101NCU05021039 |
| Date | January 2013 |
| Creators | Ching-Mou Hsiao, 蕭靖謀 |
| Contributors | Gin-Rong Liu, 劉振榮 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 89 |
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