著者

Yuta Goto Masaki Satoh

出版者

公益社団法人 日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.18A, no.Special_Edition, pp.15-20, 2022 (Released:2022-04-28)

参考文献数

31

被引用文献数

3

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We statistically investigate characteristics of “senjo-kousuitai”, quasi-stationary linear precipitation systems, in East Asia using high-resolution satellite precipitation and reanalysis data to understand whether these events are common there. We define an elongated precipitation system in the satellite precipitation data as a senjo-kousuitai event.Our results show that the contribution of senjo-kousuitai to heavy rainfall is high in western Japan, especially in Kyushu, the Nansei Islands, and the East China Sea. Among the environmental factors favorable for the occurrence of senjo-kousuitai, low-level water vapor flux and vertical wind shear are essential to the development of senjo-kousuitai. As a typical case, we examine large-scale circulations associated with senjo-kousuitai events in Kyushu in the Baiu season (June to July), and found that they are generally characterized by the intensified Pacific High over the south of Kyushu and pressure trough to the north of Kyushu. This circulation pattern results in a stronger pressure gradient and higher low-level wind speeds over Kyushu. With respect to the previously noted importance of water vapor and wind speed for better prediction of senjo-kousuitai, we show that not water vapor but higher wind speeds are the main factor for the enhancement of low-level water vapor flux.