摘要
本文利用中尺度WRF v3.2模式,通过改变中国东部京津冀、长三角、珠三角3个典型城市群下垫面类型,对大规模城市化效应进行模拟研究,探究不同纬度(不同背景环流场)不同规模的城市群发展对短期夏季高温天气的影响及可能机制,结果表明:大规模城市化后,城市扩展区近地层(地表2 m)气温均出现显著升高,城市化率越高,城市扩展面积越大,中心升温值越显著,最大升温超过了1.8℃,在不同背景风场的作用下,升温范围都向下风区扩展,长三角地区城市扩展造成的升温比京津冀强,又强于珠三角地区;城市化改变城区湿度状况,使城区出现显著干岛,湿度响应具有显著的局地性,温湿空间分布有很好的对应关系,城区整体呈现出"干暖"趋势;城市化改变地表能量平衡,使感热通量增加潜热通量减少;调整降水分布,使主城区降水较少。
By using the mesoscale WRF v3.2 model and through changing the land use types of three typical mega-cities( Beijing-Tianjin-Hebei metropolitan,Yangtze River Delta and Pearl River Delta),the large-scale urbanization effects was simulated,the influence and possible mechanism of urban agglomeration development with different scales and at different latitudes( different circulation field backgrounds) on a short range summer high temperature event were explored.Results show that the temperature at 2 m over urban areas increases significantly after large scale urbanization.The higher urbanization level is and the larger the urban expansion area is,the higher the central temperature goes up with the maximum warm exceeding 1.8 ℃.In general,under different wind fields,the warming areas all are restricted to leeward.Temperature warming of the Yangtze River Deltas is higher than those in the BeijingTianjin-Hebei metropolitan zone and Pearl River Deltas.Urbanization changes the humidity over the urban areas,so that the obvious dry island effect takes place.The humidity response depends obviously onlocation.Among different areas,a good relationship existed between changes in the regional surface temperature and humidity.Overall,urban areas have a warm and dry tendency.Urbanization effects the surface energy budget,and the sensible heat flux enhancement reduces the surface latent heat flux significantly.The precipitation distribution adjustments lead to less precipitation in main urban areas.
出处
《气象科学》
北大核心
2017年第2期161-172,共12页
Journal of the Meteorological Sciences
基金
国家重点基础研究发展计划(973计划)项目(2010CB428505)
国家自然科学基金资助项目(41275012
41475069)
关键词
城市群
夏季高温
数值模拟
Mega-cities
High temperature in summer
Numerical simulation
