【作者】 吉中会；

【导师】 查良松；

【作者基本信息】 安徽师范大学 ， 自然地理学， 2010， 硕士

【摘要】 本文利用1961~2008年长江下游沿江四个城市安庆、芜湖、南京、南通的城市站及各自周边3~4个气象站,共18个站点的年和月平均气温、平均最高气温、平均最低气温、平均相对湿度、平均风速及降水量资料,对长江下游沿江不同类型城市的气候变化特征和受城市化影响的气候变化特征进行分析;选择相关的城市化指标衡量城市化的综合水平,即城市发展指数,建立了城市气候与城市发展指数之间的关系模型。研究结果表明:(1)近四、五十年来长江下游地区沿江城市的年平均气温、年平均最高气温及年平均最低气温均呈上升趋势,其中年平均最低气温的增温速率是最大的。不同类型城市的年平均气温的增温速率随城市规模的增大而增大,具体表现为:特大城市最大,大城市次之,中等城市是相对最小的;年平均最高气温的增温速率为大城市最快,超过中等城市和特大城市;最低气温的增温随率随城市规模的增大而减小。除南京年平均最高气温所表征的热岛效应强度下降之外,四个城市的年平均气温、年平均最高气温及年平均最低气温表征的热岛效应均表现为增强趋势。年平均气温表征的热岛效应强度的变化速率表现为:中等城市的热岛效应强度增加最大,大城市次之,特大城市最小。年平均最高气温表征的热岛效应强度的增加速率则表现为:大城市最大,中等城市次之,特大城市最小。年平均最低气温的热岛效应强度增加速率为:特大城市最大,大城市次之,中等城市最小。长江中下游地区沿江地区除夏季之外,春秋冬季增温显著。通过比较四个城市四季热岛效应强度的增加速率发现,以安庆为代表的中等城市夏季对热岛效应的增温贡献率最大,以芜湖、南通为代表的大城市和以南京为代表的特大城市秋季的增温贡献率最大。(2)长江下游沿江城市年平均相对湿度逐年减小,以南京为代表的特大城市的年平均相对湿度减小速率最大,芜湖、南通为代表的大城市次之,中等城市的减小速率最小。四个城市均存在干岛效应,但其强度的变化趋势不显著。各城市四季的平均相对湿度也均呈现减少趋势,各城市的四季均存在干岛效应,且以不断增强的趋势为主导,但显著性程度不高。各季节干岛效应的变化动态与年干岛效应的变化动态基本一致。(3)随着各城市城市化水平的提高,城市及周边地区的平均风速受到一定程度的影响,年和四季的平均风速均显著减小。芜湖与南京的年平均风速减小幅度较大,安庆次之,南通最小。四个城市夏季风速的减小幅度均为最小,安庆、芜湖及南京秋季风速的减小幅度最大,南通冬季风速的减小幅度最大。(4)四个城市48年来年降水量的变化趋势均不显著,安庆、南京和南通呈弱增加趋势,芜湖则波动较大。受城市化影响的四个城市汛期降水量的波动情况与年降水总量变化情况基本一致,且变化幅度也相当。(5)长江下游沿江地区的城市发展对城市气候的影响并不完全符合库兹涅茨曲线的特征。年平均气温和年平均最低气温的热岛效应强度随城市的发展呈现先上升后下降的趋势,在一定程度上是符合库兹涅茨曲线特征的,虽然年平均最高气温的热岛效应强度变化趋势与前两者基本一致,但显著性程度相对较低。年平均相对湿度随城市发展变化趋势不明显,后期有微弱的上升趋势,年平均风速则随城市化水平不断提高而不断减小,趋势显著,两者变化趋势均不符合库兹涅茨曲线特征。(6)除南通外的其余三个城市的年平均气温、年平均最低气温的热岛效应强度与城市发展指数之间的关系的变化趋势与库兹涅茨曲线特征基本一致。南通的年平均气温、年平均最高气温及年平均最低气温的热岛效应随城市的发展在后阶段均呈现出同步增长的趋势。(7)年平均相对湿度差值与城市发展指数的关系模型除南京外显著性程度均较高。仅南通年平均相对湿度差值随城市的发展的变化趋势与库兹涅茨曲线比较一致,安庆与芜湖随城市发展相对湿度在后期均呈上升趋势,南京随城市发展表现为逐步下降趋势。(8)年平均风速与城市发展指数的关系模型相关性均较高。南通和南京后阶段的年平均风速随城市发展先增大后减小,变化基本符合库兹涅茨曲线特征。安庆和芜湖的年平均风速随城市发展先下降后上升,但芜湖后阶段上升的趋势不显著。更多还原

【Abstract】 This paper analyzed the trends of urban climate and that was influenced by urbanization in Anqing, Wuhu, Nanjing and Nantong along the downstream of Yangtze River based on data of annual and monthly mean-temperature, maximum and minimum mean-temperature, mean relative-humidity, mean wind-speed, and precipitation from 1961~2008. There was 18 stations in all, and three or four reference stations around each urban station. And this paper selected some urbanization indicators which were used to measure the comprehensive level of urbanization, which was called urban development index. Models about the relationship between urban climate and urban development index were made.Research results show that:1. The annual mean-temperature, maximal and minimum mean-temperature are all on upward trends, and the rising rate of minimum mean- temperature is the fastest in recent four or five decades. The rising rate of annual mean-temperature is faster with the urban scale extending of different cities, and it is seen as following: megalopolis >large city>medium city. The rising rate of maximum mean-temperature of the large city is faster than medium city and megalopolis. The rising rate of annual minimum mean-temperature is slower with the urban scale extending of different cities.The intensities of heat island effect about annual mean-temperature, maximal and minimum mean-temperature of four cities are increasing except annual maximal mean-temperature of Nanjing. The intensity of heat island effect about annual mean-temperature is that medium city is fastest, and megalopolis is the slowest. The intensity of heat island effect about annual maximal mean-temperature is that large city is fastest, and megalopolis is the slowest. The intensity of heat island effect about annual minimum mean-temperature is that megalopolis is fastest, and medium city is the slowest.The temperatures in Spring, Autumn and Winter are increasing prominently along the downstream of Yangtze River. Through the comparison of the increasing speeds of the intensity of urban heat island in four seasons of the four cities, the contribution rate of Summer is the biggest to the urban heat island in Anqing which represents the medium city, the contribution rate of Autumn is the biggest to the urban heat island in Wuhu, Nantong which represent the large city, and Nanjing which presents megalopolis.2. The annual mean relative-humidity is decreasing along the downstream of Yangtze River, and the decreasing speed becomes faster with the city scale extending. There are dry island effects in all four cities, though the trends are inconspicuous. The seasonal relative-humidity of four cities is decreasing, too. Though the significance is not high, there are dry island effects, and the intensities of them are increasing. The intensity trends of seasonal dried island effects are in accordance with that of annum.3. The annual and seasonal mean wind-speeds are decreasing obviously with the development of the urbanization along the downstream of Yangtze River. The decrease range of annual mean wind-speed is biggest in Wuhu and Nanjing, and that in Nantong is the smallest. The decrease ranges of summer wind-speed in four cities are the smallest, and that of autumn wind-speed in Wuhu, Wuhu and Nanjing are the biggest, and that of winter wind-speed in Nantong is the biggest.4. The trends of annual precipitation are all insignificant in recent 48 year of four cities. The trends of Anqing, Nanjing and Nantong are increasing since not obviously, and it is fluctuating in Wuhu. The trends and range of precipitation influenced by urbanization between annual and flood-season are coincident.5. The characteristics of impacts that the development of cities on the urban climate are not entirely conforming to Kuznets curve. The intensities of heat island effect about annual and minimum mean-temperatures are rising first, and then falling off, which conform to Kuznets curve to a certain extent. Although that of maximal mean-temperatures are also rising, the significance are insignificant. The trends of annual mean relative-humidity are weakly rising in the later period, and that of annual mean wind-speed are obviously decreasing with the development of the cities, and the two are not conformed to Kuznets curve.6. The trends of intensities of heat island effect about annual, maximum and minimum mean-temperatures in Anqing, Wuhu and Nanjing are in accordance with Kuznets curve except Nantong. The trends of that in Nantong are rising with the development of urbanization in the later period.7. The relationship models between annual mean relative-humidity and urbanization are significant except that of Nanjing. Only that trend in Nantong is in accordance with Kuznets curve. The trends of mean relative-humidity in Anqing and Wuhu are rising in the later period, and which in Nanjing is gradually decreasing with urbanization.8. The relationship models between annual mean wind-speed and urbanization are all significant. The trends of annual mean wind-speed with urbanization in Nantong and Nanjing are rising first, and decreasing then, which conform to Kuznets curve. And that in Anqing and Wuhu are decreasing first, and rising then, but that in Wuhu is rising insignificant in the later period.更多还原