东南沿海前汛期降水极值变化特征及归因分析

Variation of extreme precipitation and its causes during the first rainy season in the southeast coastal region of China

选取东南沿海五省(市)(上海、浙江、福建、广东和海南)79个站点1960-2012年前汛期(4-6月)的降水极值序列,将广义可加模型(GAMLSS)引入非平稳降水频率分析中,分析了降水极值的变化特征;运用主成分分析法分别构建综合气候指数和以温室气体排放量为代表的人类活动指数,同时考虑两类指数对降水极值序列变化特征的影响,运用贡献分析法和GAMLSS模型分析了气候因子和人类活动因子对降水极值变化的影响机制。结果表明:1东南沿海降水极值增加趋势显著、变异性明显增强的区域主要集中在浙江东北部、广东中北部和西部沿海、福建东部等地区;2人类活动的加剧与降水极值的变化显著相关,尤其在社会经济发达地区,在社会经济快速发展阶段(1986-2012年)人类活动对极端降水的贡献要明显大于发展缓慢阶段(1960-1985年),浙江和广东两省尤为突出;3浙江省东北部、福建省大部、广东西部沿海以及中北部地区是极端降水的高风险区,需加强对极端降水及其次生灾害的风险防范。

This study analyzed the variation of extreme precipitation by introducing Generalized Additive Models in Location, Scale, and Shape（GAMLSS） Model in the nonstationary frequency analysis based on the precipitation extreme series in the first rainy season（April, May, June） in the period of 1960- 2012 derived from 79 meteorological stations in the southeast coastal region of China which covers Shanghai, Zhejiang, Fujian, Guangdong and Hainan. The greenhouse gas emissions index represented by human activities and comprehensive climatic index were built by principal component analysis（PCA）.Simultaneously, contribution analysis method and GAMLSS model are applied to identify the impact of climate change and human activities on precipitation extremes considering both factors. The results show that：（1） The areas with significant increase and strong enhanced variation of precipitation extremes are mainly located in the northeast of Zhejiang, centralnorthern and western coastal Guangdong, and eastern Fujian.（2） There is a significant correlation between human activity increase and precipitation extreme variability, especially in the developed areas. The contribution of human activity to precipitation extremes in the stage of rapid socio- economic development（1986- 2012） is much greater than that in the stage of slow socio- economic development（1960- 1985）, especially in Zhejiang and Guangdong provinces.（3） The northeast of Zhejiang, much of Fujian and the central-northern and western coastal Guangdong are high risk areas in terms of extreme precipitation. Thus, we should strengthen the risk prevention for extreme precipitation and its secondary disasters.