【摘要】 利用乌鲁木齐市4座10层100 m梯度气象塔2013年6月～2014年4月气象观测资料和7个环境监测站AQI资料,计算并分析了大气混合层厚度和稳定度特征,探讨了大气混合层厚度和稳定度与污染的关系。结果表明:乌鲁木齐市混合层厚度夏季郊区高、城区低,冬季从南郊—城区—北郊随地势降低依次降低;夏季和冬季分别在1 559～1 772 m和526～1 156 m之间。地面至2 km以上每500 m高度间隔统计混合层厚度,500～1 000 m出现频率最多;月变化为6～9月基本在500 m以上,且每个高度区间其概率均超过10%,10月～次年2月1 500 m以上区间概率明显减小;日变化为中午13:00～16:00达到最高值,下午和傍晚迅速下降。白天较大的感热输送提供充足的热力条件,这也体现出白天以不稳定层结为主,夜间则以稳定层结为主。大气稳定度分类结果,夏季郊区和城区不稳定(A～C类)所占比例差不多,冬季北郊稳定(E、F类)所占比较最大、城区最弱。AQI指数冬季最大,从南郊—城区—北郊依次增大,这与采暖期污染物多、南郊比北郊地势高有利于扩散输送有关。总体来看,乌鲁木齐大气混合层厚度空间分布与气象要素、大气稳定度、地形等密切相关,对AQI指数分布有重要影响,这对近地层大气污染状况预报有着重要的指导意义。更多还原

【Abstract】 The meteorological observation data from four meteorological towers each of which is 100 meters high with ten layers,and AQI observation data from seven environmental monitoring stations in Urumqi City,Xinjiang,China during the period from June 2013 to April 2014 were collected and used to analyze the characteristics of the thickness and stability of the atmospheric mixed layer in this region,and their relationship with the atmospheric pollution was also analyzed.The results indicated that the thickness of the mixed layer was higher in suburbs and lower in urban areas in summer,and it was decreased along with the decrease of the terrain from the southern suburbs to the urban areas,and then to the place of the northern suburbs in winter.The thickness of the mixed layer was between 1 559 and 1 772 meters in the summer,and it was between 526 and 1 156 meters in the winter.When the thickness of the mixed layer was measured at the interval of 500 meters from the ground up to 2 km,it had the highest frequency of emergence with the height between 500 and 1 000 meters.In terms of the monthly change it was basically above 500 meters from June to September with the probability at each height interval being more than 10%.The probability at the interval above 1 500 meters was significantly reduced from October to next February.In terms of the daily variation,it was the highest from 13:00 PM to 16:00 PM and dropped rapidly after 16:00 PM.A large sensible heat transfer provided sufficient thermal conditions during the day,which was also reflected by the fact that the unstable stratification was mainly in the daytime but the stable stratification at night.When the atmospheric stability was classified,it showed that the percentage of the unstable(A-C) was almost the same between the suburban and urban areas in the summer,but in the winter the percentage of the stable(E,F) was the biggest in the northern suburbs while it was the weakest in urban areas.The AQI index was the largest in the winter,and it was increased along with the decrease of the terrain from the southern suburb to the urban area,and then to the northern suburb,which was related to the fact that there were more pollutants during the heating period,and the higher terrain in the southern suburbs is in favor of diffusing pollutants.In general,the spatial distribution of the thickness of atmospheric mixed layer was related to the meteorological elements,atmospheric stability and the terrain and it had the great influence on the distribution of AQI index.This study provided important information to the prediction of air pollution condition.更多还原