南京地区高温天气下城市化影响的模拟研究
投稿时间: 2017-06-07  最后修改时间: 2017-06-16  点此下载全文
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作者单位E-mail
马红云 南京信息工程大学 气象灾害预测评价协同创新中心 mhypony@126.com 
董轩 南京信息工程大学 大气科学学院  
孙岑霄 南京信息工程大学 大气科学学院  
基金项目:江苏省大学生创新创业训练计划平台(201510300045Z);国家自然科学基金(41641046)
中文摘要:在本文中,我们使用WRF(Weather Research and Forecasting)耦合单层城市冠层模式,研究了南京地区一次高温热浪过程(2013年8月5日至2013年8月10日)中,气溶胶的辐射效应、城市扩张对边界层的影响和它们间的相互作用。结果显示,由于气溶胶的辐射效应,在白天,南京近地面温度平均降低约0.11℃,净辐射平均降低约12W/m2;城市扩张使近地面温度增加约1.7℃,在本次试验过程中,城市扩张的增暖效应明显强于气溶胶冷却效应。另外,由于城市扩张后产生了较强的增暖作用,加强了周围气流的辐合运动,城市区域风速平均增加约0.8m/s。白天潜热通量的减少与感热通量的增加导致城市边界层内温度升高,并且城市增暖引起的上升运动将气溶胶抬升至更高层,使边界层更不稳定,气溶胶与城市边界层稳定性间可能存在正反馈。
中文关键词:数值模拟  城市扩张  气溶胶辐射效应  反馈
 
Numerical simulations of urbanization impacts under hot weather conditions in Nanjing
Abstract:Urbanization plays a vital role on local environment. In this paper, we use the Weather Research and Forecasting (WRF) model coupled with a single-layer urban canopy model (SLUCM) to investigate the radiative effect of aerosol, and the influence of urban expansion on boundary layer meteorology, as well as their interaction during the hot weather episode that intensifies urban heat island (UHI). The simulations are conducted over Nanjing, China, from 5 August to 10 August 2013. The results show that, due to the radiative effect of aerosol, 2-m temperature decreases by about 0.11oC and net radiation reduces by around 12 W/m2 at daytime in Nanjing. In addition, urban expansion increases 2-m temperature by around 1.7oC and urbanization-warming effect on 2-m temperature is stronger than aerosol-cooling effect during a hot weather episode. Because thermal effect is stronger than surface roughness effect, urban expansion increases wind speed by around 0.8 m/s in this study. Nevertheless, the decrease of latent heat flux and increase of sensible heat flux result in warmer atmosphere (below 1.6km) at daytime and urban-induced local updraft brings the aerosol to higher height in boundary layer, causing a less stable stratification. As a result, a positive feedback may exist between aerosol and urban boundary layer meteorology.
keywords:numerical simulation  urban expansion  aerosol radiative effect  feedback
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