Climatological Relationship between Warm Season Atmospheric Rivers and Heavy Rainfall over East Asia
Climatological Relationship between Warm Season Atmospheric Rivers and Heavy Rainfall over East Asia
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DOI：
10.2151/jmsj.2017-027
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发表时间：
2017-09
影响因子：
3.1
通讯作者：
Y. Kamae;W. Mei;S. Xie
中科院分区：
文献类型：
--
作者：
Y. Kamae;W. Mei;S. Xie
来自热带地区的大气水蒸气的涡旋输送对于中纬度地区的降雨和相关的自然灾害非常重要。大气河流（AR），通常与热带气旋有关的强烈水分羽流，在遇到中纬度北美和欧洲西海岸的地形时经常产生强降水。热带风暴也会在西北太平洋出现，有时会在东亚造成洪水和山泥倾泻，但热带风暴与东亚地区暴雨之间的气候关系仍不清楚。在这里，我们使用高分辨率的日降雨观测和大气再分析在1958 - 2007年期间，评估的AR的水文循环在东亚地区的贡献。尽管它们的发生率很低，但在春、夏、秋三季，AR占总降雨量的14 - 44%，占极端暴雨事件的20 - 90%。与AR相关的极端降雨在朝鲜半岛和日本的地形的西部到东南部的斜坡上特别明显，这是由于强烈的地形效应和稳定的低层水汽流动方向。自20世纪70年代以来，暖季AR强降雨和前冬季厄尔尼诺现象之间的密切关系被确定，这表明预测韩国和日本强降雨风险的潜力。
Eddy transport of atmospheric water vapor from the tropics is important for rainfall and related natural disasters in the middle latitudes. Atmospheric rivers (ARs), intense moisture plumes that are typically associated with extratropical cyclones, often produce heavy precipitation upon encountering topography on the west coasts of mid-latitude North America and Europe. ARs also occur over the northwestern Pacific and sometimes cause floods and landslides over East Asia, but the climatological relationship between ARs and heavy rainfall in this region remains unclear. Here we evaluate the contribution of ARs to the hydrological cycle over East Asia using high-resolution daily rainfall observations and an atmospheric reanalysis during 1958 – 2007. Despite their low occurrence, ARs account for 14 – 44 % of the total rainfall and 20 – 90 % of extreme heavy-rainfall events during spring, summer, and autumn. AR-related extreme rainfall is especially pronounced over western-to-southeastern slopes of terrains over the Korean Peninsula and Japan, owing to strong orographic effects and a stable direction of low-level moisture flows. A strong relationship between warm-season AR heavy rainfall and preceding-winter El Niño is identified since the 1970s, suggesting the potential of predicting heavy-rainfall risk over Korea and Japan at seasonal leads.