厄尔尼诺对中国东部季风区夏季不同持续性降水的影响

The influence of El Niño on different types of persistent summer precipitation in the eastern China monsoon region

  • 摘要: 利用1961—2018年中国地面气象台站常规观测降水数据,探讨了不同分布型厄尔尼诺事件对中国东部地区降水持续性结构的影响,进一步分析了不同区域持续性降水变化的原因。东部型厄尔尼诺事件中北异常雨带(华北、内蒙古和东北南部)主要是由于短持续性降水频率和强度同步增大造成的,短持续性降水对该区域降水异常的贡献率超过80%;南异常雨带(长江流域)形成的原因则是长持续性降水频率和累计降水日数比例同步增多。中部型厄尔尼诺事件中的异常雨带(华北南部、东北南部、黄淮和江淮地区)形成最主要的原因是短持续性降水量异常增大,其贡献占比约为60%,其次是长持续性降水,占比约为24%;短持续性降水的增加主要表现为频率增加和强度增大,而长持续性降水增加主要发生在雨带南部,是频率和累计日数比例同时增大的结果。两类厄尔尼诺事件次年夏季,中国东部地区短持续性降水的变化对总降水量异常变化的贡献最大,在长江流域长持续性降水的增强对总降水量增加也有重要作用;异常雨带形成的最主要原因是短持续性和长持续性降水频率的明显增加。

     

    Abstract: Based on daily precipitation collected at meteorological observation stations in mainland China from 1961 to 2018, impacts of different distribution types of El Niño events on persistent structure of summer precipitation over eastern China are explored, and reasons for the variation of persistent precipitation in different regions are analyzed. The north anomalous rain belt (North China, Inner Mongolia and southern part of Northeast China) corresponding to eastern Pacific (EP) El Niño events is formed mainly due to the synchronous increase of the frequency and intensity of short-persistent precipitation, and the contribution of short-persistent precipitation to the anomalous precipitation in the region exceeds 80%. The south anomalous rain belt (the Yangtze river basin) is formed mainly by the simultaneous increase of the frequency and proportion of cumulative precipitation days to total precipitation days of long-persistent precipitation. The most important reason for the formation of the abnormal rain belt (southern part of North China, southern part of Northeast China, Huanghuai and Jianghuai regions) corresponding to central Pacific (CP) El Niño events is the abnormal increase of short-persistent precipitation, which contributes about 60%, followed by long-persistent precipitation, which accounts for about 24%. The increase of short-persistent precipitation is characterized by the increases of frequency and intensity, while the increase of long-persistent precipitation mainly occurs to the south of the rain belt, which is the result of the simultaneous increase of frequency and the proportion of cumulative days. In two types of El Niño decaying summer, the variation of short-persistent precipitation in eastern China makes the greatest contribution to the abnormal variation of total precipitation, while the enhancement of long-persistent precipitation also plays an important role in the increase of total precipitation in the Yangtze river basin. The significant increases in the frequency of short-persistent and long-persistent precipitation are the main reasons for the formation of abnormal rain belts.

     

/

返回文章
返回