中国不同纬度城市群对东亚夏季风气候影响的模拟研究

Simulation of the impacts of urbanization in different areas of China on East Asia Summer monsoon climate

该工作利用中尺度模式(MM5),通过在中国东部不同地区设置城市扩展区,进行了东亚夏季风气候的模拟对比试验,以研究不同纬度带上城市化对东亚夏季风气候的影响,并试图了解不同气候背景(不同纬度)下大规模城市群(带)的气候效应及其差异.结果表明,城市下垫面扩展使得扩展区及其周边地区的降水减少、气温升高,总体上呈现出干、暖化的趋势.城市化的气候效应通过大气环流的传输可以传播到较广阔的范围.而且不同地域(纬度)的城市下垫面扩展对大范围气候的影响也具有明显差别,北方城市带扩展比南方城市带扩展对东亚气候的影响更为显著.长江三角洲地区对城市扩展造成的下垫面改变相对不敏感,因而在长江三角洲地区比较适合发展大规模城市群,而在中国北方地区,尤其是华北平原地区,则应该对城市化的规模进行适当控制,以减小城市化发展对东亚区域气候产生的不利影响.该工作的模拟结果还表明,城市带扩展对东亚夏季风有明显影响,但由城市扩展激发出的次级大气环流具有较强区域性的特点,因而难以将城市带扩展对夏季风强度的影响概括为整体增强或减弱.

The impacts of urbanization on East Asia Summer monsoon climate are simulated by using mesoscale model （MMS） with modified urban land cover in different locations of Eastern China. In the work, the contrast simulations of East Asia summer monsoon are conducted for investigating the influence of urbanization at different latitudes on East Asia summer monsoon. Trying to realize the different climatic effects of large-scale urban agglomerations in different climatic background （different latitudes）, in order to provide a reference for future rational planning size and layout of urban development to minimize the negative impact of the climatic effects of urbanization. The results show that, along with urban size increase, reduced precipitation and higher temperature are simulated over urban extended areas and its adiacent areas, and it reveals a dry and warm climate trends. The climate effects of urbanization will spread to a more expansive area by atmospheric circulation transporting. The climate effects are distinct difference conducted by urbanization in different locations （latitudes）. The urban expansion in north of China will bring a more remarkable influence on climate than that of in south. The climate is not very sensitivity to land cover changes in Yangtse river delta in some sense, and it suitable for developing mega- cities in this region. But in north China, the urban size should be controlled in order to diminish the disadvantage influences of urban exlcansion on East Asia climate. The urban expanding will induce notable influences on atmospheric circulations of East Asia summer monsoon, and the circulations evoked by urban expansion have detailed local structures. The influences of urban extended on summer monsoon climate can not be simply generalized by monsoon circulation strengthening or weakening.