城市化影响杭州城市热环境的数值模拟研究  

Simulated effect of urbanization on urban thermal environment in Hangzhou

作　　者：张含 张小伟[1] 樊高峰[1] ZHANG Han;ZHANG Xiao-wei;FANGao-feng(Zhejiang Province Climate Center,Hangzhou 310017,China)

机构地区：[1]浙江省气候中心,浙江杭州310052

出　　处：《中国环境科学》2021年第9期4107-4119,共13页China Environmental Science

基　　金：浙江省科技计划项目(2017C33072);浙江省基础公益研究计划(LGF18D050001,LQ20D050003);浙江省气象科技计划项目(2020YB04和2019ZD07);国家自然科学基金项目(42005027)。

摘　　要：通过对城市区域的气候要素进行精细化数值模拟,可以研究城市化对城市热环境的重要影响.利用WRF/UCM模式,以杭州为例,通过采用不同的下垫面土地利用分类数据,分析量化历史城市化进程对月尺度城市热环境的影响,并进一步设计了敏感性模拟试验,研究杭州地区在理想化条件下城区面积增加约2倍时,城市热环境的变化情况.模拟结果表明,杭州地区在2010~2017年的城市化进程中,城区面积约增加了1倍,导致8月热岛强度等级高于“无”(Ht>0.5℃)的区域扩大了91%,且主城区的2m平均气温增加了0.4℃,但中心城区热岛强度等级没有明显提升.杭州城区面积在2017年基础上约增加2倍时,8月热岛强度等级高于“无”的区域扩大157%,1846.4km^(2)的中心城区热岛强度等级由“弱”或“无”(Ht≤1.5℃)提升为“中等”(1.5<Ht≤2.5℃),且主城区的2m平均气温增加0.6℃.即城区面积扩大约2倍时,热岛区域范围扩大的同时,中心城区热岛强度等级提升,且城区和热岛区域面积的扩大不是等比例的.另外,城市化造成的杭州主城区的升温趋势和热岛强度的增强幅度,夜间都比日间更明显.研究表明了城市化对城市热环境的重要影响,研究结果对城市热环境领域的相关模式研究具有参考意义.We conducted high-resolution model simulations in urban areas,to investigate the important effects of urbanization on urban thermal environment.The WRF/UCM model was used to quantify the effect of past urbanization on urban thermal environment at monthly timescale for Hangzhou city,Zhejiang province,China.We also conducted sensitivity simulations to investigate the potential effects of urbanization on urban thermal environment under an idealized scenario in which urban area is tripled.In these simulations,different land use/land cover classification data were used.Simulation results show that urbanization during 2010~2017 doubles urban area at Hangzhou,leading to a 91% increase in the area with urban heat island(UHI)intensity levels stronger than“none”(Ht>0.5℃),and a rise of 0.4℃ in 2-m air temperature in the main urban area in August.If urban area is tripled from year 2017 level,the area that UHI intensity levels stronger than“none”would increase by 157%,and for 1846.4km2 of the central urban area,UHI intensity levels could be elevated from“weak”or“none”(Ht≤1.5℃)to“medium”(1.5<Ht≤2.5℃)in August.Meanwhile,the tripled urban area would increase the 2-m air temperature in the main urban area by 0.6℃.Therefore,the tripled urban area leads to the extension of UHI area,as well as the elevation of UHI intensity levels in central urban areas.Simulation results also show the disproportion between the increases of urban area and UHI area.In addition,under the impact of urbanization,relative to the daytime,the rises of air temperature and UHI intensity levels are both more noteworthy in the nighttime.Our results highlight the potentially important role that urbanization plays in urban thermal environment,providing useful insight for modeling studies on urban thermal environment and urban ecology.

关 键 词：城市化 城市气候学 城市热岛 数值模拟 

分 类 号：X16[环境科学与工程—环境科学]