中国东部不同区域城市化对降水变化影响的对比研究

IMPACT OF URBANIZATION IN DIFFERENT REGIONS OF EASTERN CHINA ON PRECIPITATION AND ITS UNCERTAINTY

城市化气候效应已经成为区域气候变化中不可忽略的人为因子。根据人口总量、人口密度和MODIS LC三种不同的分类方法划分了城市站和乡村站,利用逐日降水资料探讨了我国东部长江三角洲、珠江三角洲及京津唐等三大城市群的发展对降水变化特征的可能影响,主要得到以下结论:不同区域城市化发展对降水变化的影响存在差异;1960—2009年间,长三角和珠三角城市群城市化均有使降水变化趋势增加的作用,而京津唐城市群城市化作用不明显。不同城市化发展阶段对降水变化影响也存在差异;城市化发展慢速期(1960—1979年),城乡间降水变化趋势差异不明显,城、乡间降水变化趋势差异对城、乡站分类方法很敏感;而城市化发展快速期(1980—2009年),三大城市群的城市化发展都有使降水增加的作用,且不受城、乡站分类方法的影响。

Climate effect caused by urbanization has been an indispensable artificial factor in research on regional climate change.Based on daily precipitation data,possible effects of precipitation on the development of three urban groups in east China are discussed.With three division methods （total population,population density and MODIS land cover）,urban and rural stations are identified.The main findings are as follows.Climate effects caused by urbanization are different from place to place.In 1960-2009,the urbanization brought more precipitation to the Yangtze River Delta and Pearl River Delta city groups but had no obvious effect on the precipitation of the Beijing-Tianjin-Tangshan city group.The difference of precipitation is slight between urban and suburban areas in 1960-1979.It is more evident in 1980-2009 that urbanization has positive effects on precipitation in every city group.The difference of precipitation between urban and rural stations is sensitive to the ways of distinguishing rural from urban area,which may cause uncertainties in 1960-1979,while it is very different in 1980-2009 in which urbanization favors more precipitation in all city groups and their difference in precipitation is not sensitive to the division method.