著者

HIOKI Tomohito TSUBOKI Kazuhisa

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.2021-064, (Released:2021-07-02)

被引用文献数

2

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The central pressure fall in a typhoon is associated with the development of the warm core and mass divergence in the eye. Trajectory analyses were used to investigate the origins of air moving into the warm core and the paths of air parcels leaving the eye. First, developing Typhoon Wipha (2007) was simulated by using a high-resolution (2-km) cloud-resolving model to represent the central pressure fall and axisymmetric structures such as the warm core in the upper levels of the eye, the eyewall, and the secondary circulation. Then, using the model output data, backward trajectories were calculated from the eye; the results show that the air parcels comprising the warm core originated from the lower troposphere and the lower stratosphere. Those originating from the lower troposphere, whose equivalent potential temperature (θe) is increased by the latent heat flux from the sea, ascend through the eyewall and move inward in the upper troposphere. Those originating in the lower stratosphere, which have high potential temperature (θ), descend from the lower stratosphere to the upper troposphere. Thus, the warm core consists of high-θe air from the lower troposphere and high-θ air from the lower stratosphere. Next, forward trajectories were calculated to examine the paths of air parcels leaving the eye; the results show that air parcels leave the eye through the eyewall throughout the troposphere, particularly at heights below 2 km and between 9 and 12 km, which ultimately results in a central pressure fall.