Diurnal Variations of Summer Precipitation in the Beijing Area and the Possible Effect of Topography and Urbanization  

作　　者：殷水清 李维京 Deliang CHEN Jee-Hoon JEONG 郭文利 

机构地区：[1]State Key Laboratory of Earth Surface Processes and Resource Ecology,Beijing Normal University, Beijing 100875 [2]School of Geography, Beijing Normal University, Beijing 100875 [3]Beijing Climate Center, China Meteorological Administration, Beijing 100081 [4]Department of Earth Sciences, University of Gothenburg, Gothenburg, 40530, Sweden [5]Beijing Regional Climate Center, Beijing Meteorological Bureau, Beijing 100089

出　　处：《Advances in Atmospheric Sciences》2011年第4期725-734,共10页大气科学进展（英文版）

基　　金：supported by grants from the National Basic Key Research Program (973) under Grant No. 2006CB403606;the National Key Technology R&D Program under Grant No. 2007BAC29B04;the National Science Foundation Project for Post-doctoral Scientists of China under Grant No. 20080440343

摘　　要：The present study examined the diurnal variations of summer precipitation in the Beijing area by usingsubdaily precipitation and wind observations. A combined effect of topography and urbanization on thecharacteristics of diurnal variations was suggested. It was shown that stations located in the plain areaexhibited typical night rain peaks, whereas those in the mountainous area exhibited clear afternoon peaks ofprecipitation diurnal variations. The precipitation peaks were associated with wind fields around the Beijingarea, which were found to be highly modulated by mountain-valley circulation and urban-country circulation.The lower-tropospheric wind exhibited a clear diurnal shift in its direction from north at 0800 LST to southat 2000 LST, which reflected mountain-valley circulation. The transitions from valley to mountain windand the opposite generally happened after sunset and sunrise, respectively, and both occurred earlier for thestations located closer to mountains. By comparing the diurnal variations of precipitation at stations in anortheast suburb, an urban area, and a southwest suburb, it was revealed that the northeast suburb grouphad the highest normalized rainfall frequency, but the southwest group had the lowest from late afternoon tolate evening. On the contrary, in the early morning from about 0200 to 1000 LST, the southwest group andurban group had the highest normalized rainfall frequency. This pattern might originate from the combinedeffects of mountain-valley topography and urbanization.The present study examined the diurnal variations of summer precipitation in the Beijing area by usingsubdaily precipitation and wind observations. A combined effect of topography and urbanization on thecharacteristics of diurnal variations was suggested. It was shown that stations located in the plain areaexhibited typical night rain peaks, whereas those in the mountainous area exhibited clear afternoon peaks ofprecipitation diurnal variations. The precipitation peaks were associated with wind fields around the Beijingarea, which were found to be highly modulated by mountain-valley circulation and urban-country circulation.The lower-tropospheric wind exhibited a clear diurnal shift in its direction from north at 0800 LST to southat 2000 LST, which reflected mountain-valley circulation. The transitions from valley to mountain windand the opposite generally happened after sunset and sunrise, respectively, and both occurred earlier for thestations located closer to mountains. By comparing the diurnal variations of precipitation at stations in anortheast suburb, an urban area, and a southwest suburb, it was revealed that the northeast suburb grouphad the highest normalized rainfall frequency, but the southwest group had the lowest from late afternoon tolate evening. On the contrary, in the early morning from about 0200 to 1000 LST, the southwest group andurban group had the highest normalized rainfall frequency. This pattern might originate from the combinedeffects of mountain-valley topography and urbanization.

关 键 词：diurnal variations precipitation mountain-valley circulation urban effect Beijing area 

分 类 号：P426.613[天文地球—大气科学及气象学]