Contributing Factors of the Heavy Rainfall Event at Amami-Oshima Island, Japan, on 20 October 2010
Contributing Factors of the Heavy Rainfall Event at Amami-Oshima Island, Japan, on 20 October 2010
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DOI：
10.2151/jmsj.2014-202
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发表时间：
2014-01-01
影响因子：
3.1
通讯作者：
Kato, Teruyuki
中科院分区：
文献类型：
--
作者：
Tsuguti, Hiroshige;Kato, Teruyuki
2010年10月20日，日本奄美大岛发生了一次强降雨事件，一天内降雨量达到了创纪录的622毫米。为了阐明此次事件的潜在因素，利用观测数据、客观分析数据以及数值模拟结果，对低层湿润空气的供应机制和形成过程以及导致此次强降雨的降水系统的形成和维持机制进行了研究。这些研究表明，降雨期间，被强劲的东北东风带到奄美大岛的低层湿润空气，最初是在静止锋北侧500多公里外的东北偏东方向的低层干燥空气。这种干燥空气在向该岛移动的过程中，通过接收来自海面的大量潜热通量（气块转换）而转变为湿润空气。奄美大岛周围温暖的海面温度（比年平均温度高约2℃）促进了这种气块转换。在奄美大岛，湿润气流与早期降水系统下形成的冷池的碰撞对降水系统的形成和维持起到了重要作用，同时该岛的地形效应也起到了辅助作用。
On 20 October 2010, a heavy rainfall event occurred on Amami-Oshima Island, Japan, delivering a record 622 mm of rainfall in one day. To clarify the factors underlying this event, the supply mechanism and formation process of low-level humid air and the formation and maintenance mechanisms of the precipitation systems causing the heavy rainfall were examined using observation data, objective analysis data, and numerical simulation results. These investigations showed that low-level humid air, carried to Amami-Oshima Island during the rainfall event by strong east-northeasterly winds, originated more than 500 km to the east-northeast as low-level dry air on the northern side of a stationary front. This dry air was transformed into humid air on the way to the island by receiving large latent heat flux from the sea surface (air-parcel transformation). Warm sea surface temperatures around Amami-Oshima Island, about 2 degrees C higher than the annual mean, contributed to this air-parcel transformation. At Amami-Oshima Island, the collision of the humid flows with a cold pool formed under earlier precipitation systems contributed significantly to the formation and maintenance of the precipitation systems, supplemented by topographic effects of the island.