厄尔尼诺事件对中国夏季水汽输送和降水分布影响的新研究

发布时间：2018-10-20 07:15

【摘要】：基于1961—2016年中国地面台站降水观测资料和多种再分析资料,分析了东部型和中部型两类厄尔尼诺事件对中国夏季水汽输送和降水的不同影响。结果表明:(1)厄尔尼诺事件对中国夏季降水的影响在发生当年和次年有明显的不同,主要影响是在其发生的次年,中国大部分地区的夏季降水明显偏多。(2)东部型厄尔尼诺事件当年夏季,西北太平洋副热带高压(副高)偏东偏弱,水汽输送条件较弱,不利于中国大范围降水的发生;中部型事件当年夏季,低纬度印度洋和西太平洋蒸发异常偏强,来自阿拉伯海、孟加拉湾和西北太平洋向华南地区的水汽输送和净水汽收支增加,有利于华南地区降水的异常增多。(3)东部型厄尔尼诺事件次年夏季,副热带太平洋蒸发异常偏强,副高西伸,由于东亚-太平洋(EAP)遥相关型的建立,副高西侧的强西南气流将来自太平洋蒸发的大量水汽持续输送至中国中东部地区。此外,在东亚-太平洋遥相关型影响下中高纬度地区建立了亚洲双阻型环流,其间的低槽冷涡与上游阻高之间的强偏北气流有利于北冰洋的水汽持续输送到西北和华北北部地区,中国大部分地区净水汽收支均增加,中国北方和南方地区的降水均产生了明显的同步性增多响应,形成了南北两条异常雨带。中部型厄尔尼诺事件次年夏季,副高较常年偏西且偏北,来自太平洋蒸发的大量水汽输送到江淮地区,使其净水汽收支增加和降水偏多。因此,厄尔尼诺事件的发生不仅对长江流域和淮河流域等南方地区的降水有重要影响,对华北、东北和西北地区的降水异常也有相当的作用。
[Abstract]:Based on the observational data of precipitation at surface stations in China from 1961 to 2016 and various reanalysis data, the effects of two types of El Nino events on the summer water vapor transport and precipitation in China are analyzed. The results show that: (1) the effect of El Nino event on the summer precipitation in China is obviously different from that in the following year, and the main effect is in the following year. The summer precipitation in most areas of China is obviously more. (2) in the summer of the East-type El Nino event, the subtropical high (subtropical high) of the Northwest Pacific Ocean is weaker to the east and the condition of water vapor transport is weaker, which is not conducive to the occurrence of large-scale precipitation in China; In the summer of that year, the evaporation of the Indian Ocean and the western Pacific in the lower latitudes was very strong, and the water vapor transport and net water vapor budget increased from the Arabian Sea, the Bay of Bengal and the Northwest Pacific to South China. (3) in the summer of the eastern El Nino event, the subtropical Pacific evaporation anomaly is strong and the subtropical high extends westward, due to the establishment of the (EAP) teleconnection between East Asia and the Pacific. The strong southwest flow from the western side of the subtropical high continues to transport a large amount of water vapor evaporated from the Pacific Ocean to the central and eastern part of China. In addition, under the influence of the teleconnection between East Asia and the Pacific, the Asian double resistance circulation has been established in the middle and high latitudes. The strong northerly flow between the low trough cold vortex and the upstream resistance is conducive to the continuous transport of water vapor in the Arctic Ocean to the northwestern and northern parts of North China, and the net water vapor budget increases in most parts of China. The precipitation in the north and south of China has produced an obvious synchronous increase response and formed two anomalous rain belts in the north and south of China. In the summer of the middle type El Nino event, the subtropical high is westerly and northward, and a large amount of water vapor evaporated from the Pacific Ocean is transported to the Jianghuai region, which results in the increase of net water vapor budget and the increase of precipitation. Therefore, the occurrence of El Nino event not only has an important impact on precipitation in the Yangtze River Basin and the Huaihe River Basin, but also plays an important role in the precipitation anomalies in North China, Northeast China and Northwest China.
【作者单位】：中国气象科学研究院;南京信息工程大学大气科学学院;国家气候中心;
【基金】：国家重点基础研究发展计划(973)项目(2013CB430202) 国家自然科学基金资助项目(41401056和41275095) 公益性行业(气象)科研专项(GYHY201406001和20140618) 江苏省普通高校研究生科研创新计划项目(KYLX15_0858)
【分类号】：P426;P732

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