城市植被对冬季气象要素影响的数值模拟研究  

Numerical simulation study of the impact of urban vegetation on regional meteorological conditions in winter

作　　者：杨健博 刘红年[2] 孙鉴泞[2] YANG Jianbo;LIU Hongnian;SUN Jianning(Tianjin Institute of Meteorological Science,Tianjin 300074,China;School of Atmospheric Sciences,Nanjing University,Nanjing 210023,China)

机构地区：[1]天津市气象科学研究所,天津300074 [2]南京大学大气科学学院,南京210023

出　　处：《气象科学》2018年第5期575-584,共10页Journal of the Meteorological Sciences

基　　金：国家重点基础研究发展规划(973)项目(2014CB441203);国家自然科学基金资助项目(41575141);江苏省气候变化协同创新中心资助资金

摘　　要：为认识并量化城市地区自然植被对城市气象特征的综合影响及其在不同季节的变化趋势,本文基于区域边界层模式(Regional Boundary Layer Model,RBLM),利用敏感性数值试验的方法量化评估了冬季背景下,城市植被对苏州地区气象要素的综合影响,及其在不同绿化情境下的变化特征。研究结果表明:冬季城市植被会导致气温及城市热岛强度的下降,下降幅度随着植被覆盖率的提高而增大,当市区树木覆盖率分别为0、20%和40%时,日平均城市热岛强度分别为1. 8、1. 4和1. 0℃。与苏州市真实绿化情境相比,市区树木覆盖率分别为20%和40%的理想试验方案,可以导致市区日平均气温分别下降约0. 23℃和0. 84℃。城市植被还会通过叶面及土壤表面的蒸发蒸腾作用,增加空气中的水汽含量,当市区树木覆盖率分别为0、20%和40%时,中午时空气比湿分别为2. 46、2. 61和2. 78 g·kg^(-1)。相同覆盖率条件下,草地绿化方案对气温和空气湿度的影响要明显弱于树木。城市植被会对区域地表能量平衡过程产生明显影响,使到达地面的太阳辐射减少,地面温度降低。当树木覆盖率分别为0、20%和40%时,中午地表净辐射通量最大值分别为433、382和332 W·m^(-2)。地面温度的下降以及植被、土壤的蒸发蒸腾作用,使感热减少,潜热增加。自然植被对城市气象要素的影响在冬季要明显弱于夏季。To comprehensively investigate and quantify the impact of urban vegetation on regional meteorological conditions and its seasonal variation tendency,the sensitivity numerical value test was used based the RBLM(Regional Boundary Layer Model)to evaluate the impact of urban vegetation on the meteorological conditions of Suzhou in winter as well as its change features under different coverage patterns.The results indicate that urban vegetation would contribute to a reduction of air temperature and Urban Heat Island Intensity(UHII),and this effect would be amplified with the increase of vegetation coverage.Modeled daily mean UHII reaches 1.8,1.4 and 1.0℃under tree coverage of 0,20%and 40%,respectively.Compared to the real coverage patterns of vegetation in Suzhou,the ideal greenery scenarios with tree coverage of 20%and 40%could lead to a reduction of 0.23℃and 0.84℃in daily mean air temperature.Urban vegetation may also increase the canopy humidity through the evaporation and transpiration effect on leaf and ground surfaces.By increasing tree coverage from 0 to 20%,and then to 40%,the specific humidity at noontime is 2.46,2.61 and 2.78 g·kg^-1.Tree planting is generally more notable in modifying ambient temperature and humidity than grass surfacing with the same coverage.Trees could also affect the surface energy balance by reducing the amount of solar radiation that reaches the ground surface,hence reducing the surface temperature.The surface net radiation flux at noon is 433,382 and 332 W·m^-2 when the tree coverage is 0,20%and 40%,respectively.In addition to the reduction of surface temperature,the evaporation and transpiration effect of vegetation would also contribute to the decrease of sensitive heat flux as well as the increase of latent heat flux.The meteorological effect of urban vegetation is more notable in summer than in winter.

关 键 词：城市植被 城市热岛 RBLM 

分 类 号：X16[环境科学与工程—环境科学]