高度城市化地区的降水集中度研究——以长三角城市群为例

Precipitation Concentration in Highly Urbanized Regions——Case Study of Yangtze River Delta Urban Agglomeration

在全球变暖和人类活动的背景下,降水在年内分布上发生了比较大的变化,对人民生产生活产生了巨大的影响,这一影响在城市化较高的地区尤为明显。基于多源降水数据(降水产品数据和气象站点数据)和夜间灯光数据,选定中国的长三角城市群作为研究区域,将基尼系数(Gini Index,GI)作为降水集中度的指标,利用Theil-Sen Median斜率估计和Mann-Kendall显著性检验进行趋势分析,最后通过相关性分析探究城市化程度与降水集中度的关系。研究结果表明:(1)CHIRPS(Climate Hazards Group InfraRed Precipitation with Station Data)数据计算得到的GI与站点数据结果的均方根误差为0.036,远小于CMFD数据(0.067)和MSWEP数据(0.083)的结果,表明CHIRPS数据具有最佳的适用性;(2)长三角城市群的降水不均匀性从南向北逐渐增加,并在城市群中部和西部呈现出显著上升的趋势,研究区域内的降水年内分布将会朝着集中分布的方向发展,极端降水事件出现的可能性增加;(3)城市化对降水集中度主要起到促进作用,城市的快速发展使得降水不均匀性增强,并且在城市群内的南京市、无锡市和镇江市等地区更为显著,更有可能发生城市内涝等灾害。研究对于城市的防洪设计、城市道路排水管道的设计和城市防洪应急响应预案的编制具有参考意义。

Amid global warming and enhanced human activities,precipitation has undergone significant changes in its intra-annual distribution,exerting a considerable impact on people s livelihoods and productivity,particularly in highly urbanized regions.This study focuses on the Yangtze River Delta urban agglomeration in China and utilizes multiple sources of precipitation data(including precipitation product data and meteorological station data)along with nighttime light data.The Gini Index(GI)is employed as an indicator of precipitation concentration.The Theil-Sen Median slope estimation and Mann-Kendall significance test are utilized for trend analysis,and a correlation analysis is employed to explore the relationship between urbanization levels and precipitation concentration.The results show that:①the root mean square error between the GI calculated from climate hazards Group infrared precipitation with station data(CHIRPS)and the station data results is 0.036,significantly lower than the results from CMFD data(0.067)and MSWEP data(0.083),which indicates that CHIRPS data demonstrates optimal applicability.②The unevenness of precipitation in the Yangtze River Delta urban agglomeration gradually increases from south to north,with a significant increasing trend in the central and western parts of the agglomeration.The intra-annual distribution of precipitation in the study area has become more concentrated,leading to an increased likelihood of extreme precipitation events.③Urbanization is likely to promote the concentration of precipitation.The rapid development of cities enhances precipitation unevenness,especially in areas such as Nanjing,Wuxi,and Zhenjiang,making them more susceptible to urban flooding and related disasters.The findings of this research have practical implications for urban flood control design,urban road drainage system planning,and the development of emergency response plans for urban flood control.