近60年中国持续极端降水时空变化特征及其环流因素分析

极端降水具有较强的持续时间不确定性，持续多天的极端降水事件往往具有较大的致灾性，但目前从极端降水持续性角度进行极端降水变化及其环流因素的研究还非常缺乏。利用1961~2018年中国逐日降水格点数据集以及大气环流指数数据，定义持续了2天及以上的极端降水为持续极端降水事件，研究其在中国不同区域发生频次、持续日数以及持续极端降水总量、持续极端降水最大降水量的时空变化和影响因素。结果表明：（1）近60年来，中国持续极端降水事件在较为干旱的地区(蒙新地区、青藏地区)高发且持续时间长，但在较湿润的地区（东部地区）持续极端降水事件强度更高。（2）中国持续极端降水事件的频率和强度均呈现出增加的趋势，但在区域尺度上，东部地区没有明显的变化趋势，越干旱的地区增加趋势越大。各个指数变化趋势的空间分布格局相似。（3）持续极端降水事件对总降水的贡献率呈现出缓慢的增长趋势，东部地区增长趋势不明显。（4）西太平洋副高、南海副高、西太平洋暖池、亚洲区极涡、北半球极涡和中国持续极端降水事件有着显著的相关关系。区域尺度上，西太平洋副高对蒙新地区和青藏地区的影响最大，东部地区则受到西太平洋副高和西太平洋暖池的较大影响。总体上西太平洋副高对于中国持续极端降水事件影响最大，西太平洋副高强度的加强往往会引起中国持续极端降水增多。

Spatio-temporal Change of Persistent Extreme Precipitation and the Associated Circulation Causes Over China in the Last 60 Years

Extreme precipitation usually has strong uncertainty of duration. The extreme precipitation event persisting for multi-days may cause great disaster. However, there is a lack of research on extreme precipitation variation and its circulation factors from the perspective of extreme precipitation persistence. Based on the daily precipitation grid data set and atmospheric circulation index data from 1961 to 2018 in China, this study defines extreme precipitation lasting for 2 days or more as persistent extreme precipitation events. We analyze the spatio-temporal changes and causes of the occurrence frequency, number of persistent days, total annual persistent extreme precipitation and maximum annual persistent extreme precipitation in different regions of China. The results show that: (1) In the past 60 years, persistent extreme precipitation events in China have a high incidence and a long duration in the arid regions (Mongolia-Xinjiang region and Qinghai-Tibet region), while the intensity of persistent extreme precipitation events is higher in the humid regions (eastern region). (2) The frequency and intensity of persistent extreme precipitation events in China show an increasing trend. However, on the regional scale, there is no obvious change trend in the eastern region. The drier the region, the greater the increase trend. The spatial distribution patterns are similar among index change trends. (3) The contribution rate of persistent extreme precipitation events to the total precipitation shows a slow growth trend which, however, is not obvious in the eastern region. (4) There are significant correlations between the western Pacific subtropical high, the South China Sea subtropical high, the western Pacific warm pool, the Asian polar vortex, the northern hemisphere polar vortex and the persistent extreme precipitation events in China. On the regional scale, the western Pacific subtropical high has the greatest impact on Mongolia-Xinjiang region and Qinghai-Tibet region, while the eastern region is greatly affected by the western Pacific subtropical high and the western Pacific warm pool. Generally speaking, the western Pacific subtropical high has the greatest impact on China's persistent extreme precipitation events, the strengthening of the western Pacific subtropical high will lead to more persistent extreme precipitation in China.