长江三角洲城市群对夏季日降水特征影响的模拟研究  

Simulation study of urbanization effects on summer daily precipitation over the Yangtze River Delta

作　　者：敖翔宇[1] 任雪娟[1] 汤剑平[1] 杨修群[1] 

机构地区：[1]南京大学大气科学学院,南京210093

出　　处：《气象科学》2011年第4期451-459,共9页Journal of the Meteorological Sciences

基　　金：国家重点基础研究发展计划(973计划)项目(2010CB428504)

摘　　要：利用耦合了单层城市冠层模型UCM的中尺度模式WRF,探讨了长江三角洲地区城市化对夏季日降水特征的影响。结果表明,WRF模式能较好地再现长三角地区2003—2007年夏季降水的空间分布,比较成功地模拟出了降水中心的位置及强度。城市化使得长三角地区夏季降水日数减少了1～5 d,这种降水日数的减少主要是由于城市化使小雨日数减少引起。城市化增强了长三角大部分地区的日降水强度。进一步对长三角地区4个典型城市群宁镇扬、苏锡常、上海和杭州湾城市群进行了夏季降水日变化分析,得出城市化对降水日变化的影响存在一定的区域差异。对于长三角整个大城市群,城市化对降水量、降水强度日峰值出现时刻以及降水强度日峰值大小无明显影响,而使得降水量日峰值减少。城市化使得苏锡常地区降水量日峰值略有增加,宁镇扬和上海地区降水量日峰值都减小,而杭州湾城市群区降水量日峰值出现时刻延后。城市化使得4个典型城市群降水强度日变化曲线形态发生改变,使得上海地区降水强度日峰值出现时刻延后,使得杭州湾城市群区夜雨增强。In this paper,the Weather Research and Forecasting（WRF）model coupled with a single-layer urban canopy model（UCM）is used to investigate the urbanization effects on summer daily precipitation over the Yangtze River Delta area.The results show that the WRF model can quite well reproduce the summer precipitation over the Yangtze River Delta area.The simulated spatial distribution and the intensity of the summer precipitation over a period of 5 years（2003—2007）agree well with the observation.Urbanization results in significant decrease in the rainfall days over the Yangtze River Delta area by 1-5 days.It is mainly caused by the reduction of the minor rainfall days.The daily rainfall intensity is increased over most part of Yangtze River Delta area.The analysis of the rainfall diurnal cycle of the four typical urban subgroups in Yangtze River Delta area shows that there exist some regional differences for the urbanization effects.For the whole Yangtze River Delta city group,urbanization has no significant effects on the occurrence times of the rainfall amount and rainfall intensity daily peak,but results in a decrease of daily peak of the rainfall amount.Urbanization results in a slight increase of daily peak of the rainfall amount over SXC area,but a decrease over NZY and SH area.The occurrence time of the rainfall amount daily peak is delayed over HZW area.Urbanization also changes the shapes of the rainfall intensity diurnal variation over the four typical city subgroups.It causes a delay of the occurrence time of the rainfall intensity daily peak in SH,an increase in the nocturnal rainfall intensity in HZW.

关 键 词：城市化 降水 WRF模式 

分 类 号：P461.8[天文地球—大气科学及气象学]