- 著者
- WANG Chung-Chieh LIN Kuan-Yu DAVIS Christopher A. HUANG Shin-Yi LIU Stefano Chih-Shin TSUBOKI Kazuhisa JOU Ben Jong-Dao
- 出版者
- Meteorological Society of Japan
- 雑誌
- 気象集誌. 第2輯 (ISSN:00261165)
- 巻号頁・発行日
- pp.2020-036, (Released:2020-04-20)
- 被引用文献数
- 2
In this study, the impacts of Typhoon Morakot (2009)'s vortex structure on the extreme rainfall in Taiwan are investigated through an application of piecewise potential vorticity (PV) inversion. The control (CTL) experiment, starting at 0000 UTC 7 August or 15 h before landfall, reproduces the event realistically and is validated against the observations. By altering the PV perturbation inside 750 km from its center, we conduct sensitivity experiments in which the size and/or circulation strength of Morakot is reduced/weakened in the initial field in several different ways. In the sensitivity tests, particularly those where the initial PV within the inner core (≤ 250 km) is significantly weakened, the storm makes landfall earlier, stays over land longer, and exits Taiwan later. Such track changes are accompanied by a contraction and spin-up of the inner core at early stages of the integration, caused by convection/latent heating within the inner core under large-scale low-level southwesterly flow. As a result, Taiwan receives an overall rainfall amount either comparable to, or even more than (up to +12 %), CTL in all tests. Thus, a weaker Morakot does not necessarily lead to less total rainfall over Taiwan, and the strong southwesterly flow and its moisture supply were bigger factors than the vortex structure in this event. On the other hand, the rainfall in the southern Central Mountain Range on 8 August, which were the most-rainy area and period in reality, tended to decrease by up to 40 % with the contraction and a weaker outer circulation. Thus, the rainfall patterns and evolution in the sensitivity tests are considerably different than those in CTL, indicating that the vortex structure plays an important role in the rainfall of this region.
- 著者
- Hor Tai-Hwa Chang Mou-Hsiang Jou Ben Jong-Dao
- 出版者
- 社団法人日本気象学会
- 雑誌
- Journal of the Meteorological Society of Japan. Ser. II (ISSN:00261165)
- 巻号頁・発行日
- vol.76, no.4, pp.473-496, 1998-08-25
- 参考文献数
- 42
- 被引用文献数
- 1
TAMEX IOP期間中(1987年6月15日)に台湾の東岸沖で研究用航空機(NOAA P-3)を用いて梅雨前線の鉛直断面(6高度)観測を実施した。航空機による直接観測データと2種類の航空機搭載レーダーのデータを用いて、梅雨前線南端付近のメソスケール構造と、前線の維持機構を調べた。各高度における水平飛行中の乱流強度の急増から前線の先端の位置を決定し、前線の移動速度を考慮に入れて、前線を横切る鉛直断面内の運動学、力学及び熱力学変数の分布を合成した。これらの分布から、前線の先端部は風速の水平成分と空気密度の偏差の等値線に平行で、密度流的な構造を示すことが明らかとなった。熱力学変数の変化はさほど顕著ではないが、相当温位の分布は前線後面の下層の寒気コアの存在を示した。寒気コアは最も空気密度の大きな部分に対応していた。密度流の進行及び前線系の維持のメカニズムとして、寒気コア内における後方から前方に向かう水平気圧傾度力、前線の先端部付近における中程度の対流不安定、平均流からの運動エネルギーの変換が考えられる。