中国年和季节极端降水时空特征 及极值分布函数上尾部性质

基于热带气旋时间、路径、强度数据和中国728个气象站点1951~2014年日降水数据,分析了年和季节极端降水广义极值（GEV）分布函数特征及受热带气旋的影响。通过检查年和各季节极端降水的非一致性,发现具有变异点或显著时间趋势的站点占总站点数的比例较低。仅考虑满足一致性的站点,年和各季节极端降水GEV分布上尾部在全国大部分区域表现出厚尾特征,且不具有上边界。总体来看北方厚尾特征重于南方,秋季和冬季明显高于年和夏季。年极端降水厚尾特征受到不同季节极端降水机制的混合影响。而且,热带气旋对中国沿海区域极端降水有重要影响,往往引发大量级极端降水。东南沿海地区最大10场极端降水由热带气旋引发的比例达到60%以上。因此热带气旋趋向于增加沿海区域年极端降水GEV分布形状参数的大小,并控制着曲线上尾部的形状。

Spatiotemporal Patterns of Extreme Precipitation Distributions with Annual and Seasonal Scales and Potential Impact of Tropical Cyclones in China

Based on the daily precipitation and tropical cyclones data in 728 stations from 1951 to 2014 in China, spatio-temporal patterns of extreme precipitation Generalized Extreme Value (GEV) distribution with annual and seasonal scales and potential relationships with tropical cyclones were analyzed. We examined the nonstationarity in annual and seasonal extreme precipitation and found that the frequency of stations with change point or significant temporal trend on total 728 stations was small. For stations with stationary in annual and seasonal extreme precipitation, the distribution curves of annual and seasonal extreme precipitation had thick upper tails and unbounded. And the upper tails in north of China were thicker than south of China with bigger in autumn and winter than annual and summer. However, the thick tails at annual scale were influenced by seasonal extreme precipitation. In addition, tropical cyclones play an important role in extreme precipitation generating mechanisms on China's coastal regions, which often caused precipitation with bigger magnitude. More than 60% of the ten largest annual precipitation extremes were caused by tropical cyclones. Therefore, anomalously large values of the GEV shape parameter estimates were linked to the role of tropical cyclones in controlling the upper tail of extreme precipitation distributions.