城市化对南京气候影响的数值模拟研究

利用MODIS下垫面资料和NCEP-FNL再分析资料,采用四层嵌套,通过WRF(Weather Research and Forecasting Modeling System)模式,模拟研究了城市化对南京气候的影响。结果表明:城市土地利用类型的改变使下垫面热力、动力属性发生改变,影响了地表与大气之间的动量和热量交换,进而对局地气候特征产生影响。城市化后南京城市热岛效应明显增强,1月和7月2m气温有明显增加的趋势,边界层高度分别增加了约60m和180m 。土地利用类型改变使地表粗糙度增加,1月和7月地面风速分别减小了1.1m·s^-1和0.7m·s^-1 ,并且地面辐合得到加强。城市化使城市地区的中雨和大雨发生概率增加而小雨发生概率减少,中雨和大雨天数最大分别增加约8天和4天。

Numerical Simulation Study on Climate Impacts of Urbanization in Nanjing

The influence of urbanization on the climate of Nanjing was studied by numerical simulation of WRF model,while using MODIS land surface data and NCEP FNL reanalysis data,adopting four layers of nesting.The results showed that the change of land use type in urban caused the change of thermodynamic and dynamic properties in urban underlying surface,which affected the momentum and heat exchange between the surface and the atmosphere,and the local climatic characteristics in advance.The heat island effect was enhanced obviously,the 2 m temperature significantly increased in January and July,and the height of the boundary layer increased by about 60 and 180 m.The surface roughness increased with the change of land use type,the ground wind speed decreased by 1.1 m·s-1 and 0.7 m·s-1 in January and July,respectively,and the ground convergence was strengthened.Urbanization increases the probability of moderate and heavy rain in urban areas while decreases the probability of light rain. The number of moderate and heavy rain days increases by up to 8 and 4 days respectively