摘要
应用北京地区20个常规地面气象站、2个自动气象站和中国科学院大气物理研究所325m气象铁塔的资料,对北京2003年7月热岛状况进行了统计分析,发现北京夏季夜间存在强热岛效应,夏季夜间存在强热岛效应的天数占到了31,强弱热岛天数合计占到了大约45。进一步分析7月1日强热岛特征及其气象影响因子,结果表明:夜间存在强热岛时,郊区所有测站的地面气温都要低于主城区地面气温,城市强热岛的高温中心在天安门和白家庄连线的主城区;白天日照充足的晴夜,日落后城区320m以下低层大气存在逆温和弱的风速,城区地面气温下降速率和幅度均远小于郊区,城市强热岛因此得以形成和维持。日出后至正午,北京北部郊区日照时间比城区长,郊区地面大气得到来自太阳辐射的能量多于城区,而太阳辐射的加热作用使城区低层大气逆温消失,大气稳定度减弱,并使郊区地面气温上升速率和幅度大于城区,最终导致夜间出现的强热岛减弱、消失。此外,应用MM5模式对强热岛进行了初步数值模拟研究,发现在MM5中考虑城市人为热和热储存,可以改善模式对热岛的数值模拟,表明城市人为热和热储存在夏季强热岛的形成中有重要作用。
Based on the data of 20 meteorological stations and two automatic stations and the data of 325m meteorological tower of IAP, characteristics of Beijing urban heat islands （UHI） in July, 2003 are analyzed. The results show that strong urban heat islands occur in the night in July over Beijing under some specific weather conditions. The days with strong urban heat islands occupy about 1/3 of the total days. In addition, the characteristics and influencing factors of a strong urban heat island are analyzed in details. Results show that the UHI center lies over the urban area surrounding Tiananmen, Baijiazhuang, and the strong UHI occurs in the clear sky night with strong sunlight in the daytime. The weak wind and the temperature inversion are very important to the formation and maintenance of a strong UHI. But in the next daytime, the temperature inversion disappeared, and the amount of sunlight in northern suburb is more than that in the urban area, which makes the surface temperature of suburban atmosphere rise faster and higher than that of the urban surface atmosphere, and the intensity of UHI weaker. In addition, the strong urban heat island was simulated with MM5. And the results show that when only the physical properties such as the roughness of the underlying surface were considered in MM5, simulated the urban surface temperature and the intensity of VIII don＇ t accord with the observational data. However when the anthropogenic heat and urban heat storage are taken into account, the numeric simulation of UHI could be improved effectively. The anthropogenic heat and urban heat storage play very important role in the formation of the strong UHI in the night.
出处
《气象》
CSCD
北大核心
2007年第6期25-31,共7页
Meteorological Monthly
基金
国家自然科学基金重点项目40233030
关键词
城市热岛
逆温
弱风
人为热
热储存
数值模拟
MM5
urban heat island temperature inversion weak wind urban ant urban heat storage numerical simulation MM5
