近56年中国极端降水事件的时空变化格局

Spatio-temporal Patterns of Extreme Precipitation Events over China in Recent 56 Years

基于中国693个地面观测站1961-2016年的逐日降水资料,全面分析了全国和各分区极端降水事件、连续性极端降水事件及其起止时间的时空分布和变化特征。结果表明,近56年,全国极端降水事件明显增多,极端降水量和极端降水日数呈增加趋势的站点占总站数的68%,且主要集中在东南沿海和西部地区。华东地区是全国极端降水量增长幅度最大的地区,增速达18. 2 mm·(10a)^-1,西北地区的极端降水日数增速最快,每10年增加0. 37天。全国平均的连续性极端降水事件表现为不显著的增加趋势,其中仅西北地区的连续性极端降水量和降水频次的增加趋势达到0. 01显著性水平,华北和西南地区的连续性极端降水事件表现为不显著的下降趋势。全国平均的极端降水事件的开始时间和结束时间分别呈现出明显的提前和推迟趋势,西北、青藏和东北地区极端降水事件的开始时间显著提前,西北地区的结束时间显著推迟,受其影响,西北地区的极端降水事件持续期增长幅度最大达到10. 4 d·(10a)^-1。

Using the daily precipitation datasets of 693 observational stations during the period of 1961-2016,this paper analyzed the spatio-temporal patterns and variations of the extreme precipitation events,persistent extreme precipitation events and their start and end dates in China. The results showed that the extreme precipitation events increased significantly in the past 56 years in China,and the increasing trends of the amounts and days of extreme precipitation were observed at about 68% of the stations,which were mainly located in the southeastern coastal and Western China. The largest increase of extreme precipitation amounts was observed in Eastern China,with an increasing trend up to 18. 2 mm·(10 a)^-1,while the most significant increase of extreme precipitation days was observed in Northwestern China,with an increasing trend of 0. 37 d·(10 a)^-1. The variation of persistent extreme precipitation events averaged over China was characterized by insignificant increasing trend. The significant increasing trends of the amounts and frequencies of persistent extreme precipitation at the99% confidence level were only observed over the Northwestern China,while the Northern China and Southwestern China showed insignificant decreasing trends. The start and end dates of extreme precipitation events averaged over China showed obvious advance and delay trend,respectively. The significant advance of start dates was found in Northwestern China,Qinghai-Tibetan Plateau and Northeastern China,and the significant delay of end dates was observed in Northwestern China,which led to an increase in the duration of extreme precipitation events in Northwestern China,with the largest rate of 10. 4 d·(10 a)^-1.