华中地区大气环境的多源观测资料气候分析及模拟研究

发布时间：2018-06-09 05:32

本文选题：华中地区 + 气候分析　；参考：《南京信息工程大学》2016年硕士论文

【摘要】：本文使用华中(河南、湖北和湖南)三省1962～2011年霾日逐日地面观测资料、2005～2014年MODIS卫星遥感气溶胶产品,分析了该区域霾污染和大气气溶胶光学厚度(AOD)、Angstrom波长指数(α指数)和细粒子比(FMF)的气候特征。基于WRF-Chem模式,搭建了华中区域空气质量预报系统。使用该系统模拟了长江中游城市群地区发生于2014年11月18日～25日的一次重霾污染过程,分析城市化下垫面改变对霾污染中气象要素和大气气溶胶浓度的影响,得到以下主要结论：(1)华中地区的霾高发中心位于河南中北部、湖北中西部和湖南中部人口集中的气溶胶浓度高值区,其中霾日数最多的站点为河南新乡,年均达到79.1 d。霾的季节性变化表现为冬季霾日数最多,夏季最少,霾污染是典型的冬季大气环境事件。但随着近年春夏秋三季霾日的增加,华中地区霾污染的季节性差异减小。城市地区是华中霾污染严重的区域。近50年污染地区霾发生频率增多,而相对清洁地区霾污染发生频率减少。华中地区大气环境呈现出两极分化的变化特征。近50年来华中地区霾日增加受人为污染物排放加强和东亚季风减弱的共同影响。(2)华中地区AOD的年均分布为东高西低,α指数和FMF的分布均为西高东低。人口稠密的大城市地区AOD较高,α指数和FMF较低,而人口稀疏的华中西部AOD较低,α指数和FMF较高。AOD在春夏两季较高,在秋冬两季较低。a指数和FMF在夏秋两季较高,冬春两季较低。华中地区10年间的AOD整体表现为下降趋势,α指数和FMF值呈升高趋势。华中大部分地区春秋两季AOD显著降低,春冬两季的α指数和FMF显著升高。相对清洁的站点在这10年间AOD呈下降趋势,而FMF则无显著变化趋势。(3)使用搭建的空气质量预报系统模拟发现,城市化下垫面的改变加重了霾污染事件中,长江中游城市近地面大气颗粒物的霾污染水平。城市扩张导致下垫面的粗糙度增加,减弱了城市地区近地面风速,不利于污染物从城市源区向下风方向输送。下垫面改变为城市之后,14时的平均气温和边界层高度升高,2时则表现为下降,下垫面性质的改变使得夜间降温幅度明显。此外,城市下垫面改变使得大气颗粒物浓度的增加主要发生在500m高度以下的大气边界层内。
[Abstract]:In this paper, MODIS satellite remote sensing aerosol products are used in three provinces of Central China (Henan, Hubei and Hunan) from 1962 to 2011. The climatic characteristics of haze pollution and aerosol optical thickness (AOD) Angstrom wavelength index (伪 index) and fine particle ratio (FMF) in this area are analyzed. Based on the WRF-Chem model, a regional air quality prediction system for central China is built. The system is used to simulate a heavy haze pollution process in the urban agglomeration area of the middle reaches of the Yangtze River from November 18 to 25, 2014. The influence of the change of the underlying surface of urbanization on the meteorological elements and atmospheric aerosol concentration in haze pollution is analyzed. The main conclusions are as follows: (1) the haze high incidence center in central China is located in the high concentration area of aerosol concentration in central and central Hubei Province and central Hunan Province, and the site with the highest haze days is Xinxiang, Henan Province, with an average annual average of 79.1 days. The seasonal variation of haze is the most haze days in winter and the least in summer. Haze pollution is a typical atmospheric environmental event in winter. However, with the increase of haze days in spring, summer and autumn in recent years, the seasonal difference of haze pollution in central China decreases. Urban areas are the most polluted areas in central China. In the last 50 years, the frequency of haze in polluted areas increased, but decreased in relatively clean areas. The atmospheric environment in central China is characterized by polarization. In the last 50 years, the increase of haze in central China is influenced by the enhancement of anthropogenic pollutant emission and the weakening of East Asian monsoon.) the average annual distribution of AOD in central China is lower than that in East China, and the distribution of 伪 index and FMF are both low in West China. AOD is higher, 伪 index and FMF are lower in densely populated metropolitan areas, and AOD is lower in middle west of China, and 伪 index and FMF are higher in spring and summer, lower in autumn and winter, and lower in winter and winter. In central China, AOD showed a downward trend, and 伪 index and FMF showed an increasing trend during the past 10 years. AOD decreased significantly in spring and autumn, and 伪 index and FMF increased significantly in spring and winter in most areas of central China. The relatively clean stations showed a decreasing trend of AOD in the past 10 years, while FMF showed no significant change trend. (3) using the air quality prediction system built up, it was found that the change of the underlying surface of urbanization aggravated the haze pollution events. Smog pollution levels near the surface of atmospheric particulates in the middle reaches of the Yangtze River. Urban expansion leads to an increase in the roughness of the underlying surface, which weakens the wind speed near the ground in urban areas and is not conducive to the downward wind transport of pollutants from the source area of the city. After the change of the underlying surface into a city, the average temperature and the height of the boundary layer increased at 14:00 and decreased at 2. The change of the properties of the underlying surface made the temperature drop obviously at night. In addition, the change of the underlying surface of the city results in the increase of atmospheric particulate concentration mainly in the atmospheric boundary layer below 500m height.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X513;X87

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