基于激光雷达的杭州市区不同强度霾探测研究

发布时间：2018-05-07 02:36

本文选题：霾 + CALIPSO卫星　；参考：《浙江大学》2014年硕士论文

【摘要】：随着我国经济发展和城市化进程的推进,低能见度天气已成为当前国内众多城市面临的重要环境问题,霾也由原来的天气状态升级为一种污染现象。目前对于霾的观测主要依赖于地面观测站点和光学遥感提供空气质量与霾污染范围,而对霾天大气气溶胶垂直分布的探测相对较少。美国国家航空航天局(NASA)和法国国家航天中心(CNES)2006年发射的“云-气溶胶激光雷达红外开拓者(Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations,CALIPSO)"卫星提供了较高垂直分辨率和测量精度的全球云和气溶胶观测数据,为研究霾过程中大气气溶胶的垂直分布特征提供了有效监测手段。本文根据杭州地区7个常规气象站气象资料、空气污染指数资料等实测资料,按照《霾的观测和预报等级(QX/T113-2010)》标准整理研究了杭州市霾天气的历史演变情况及其季节变化和月变化特征；并利用星载激光雷达数据分析了杭州市区无霾与不同程度霾天的大气垂直结构特征,得到基于星载激光雷达探测城市霾的方法。研究工作主要有以下4个结论： (1)杭州市霾天气时间演变特征： 1951年-2010年杭州市霾天数历史演变过程可分为3个阶段：1951-1964年的环境恢复期,1965-1975年的稳定期和1975年后的霾天天数快速增长期。霾天天数的季节变化特征为：冬季春秋夏季,这主要是受到杭州市气候条件的影响。霾天数的月变化特征为：1月和12月最容易发生霾过程,7月份霾多年平均发生次数相对最少。 (2)杭州市区大气垂直分布特征：随着高度的上升,大气后向散射系数、体积退偏振比和色比等光学参数的取值减小,气溶胶的不规则性减弱。各高度层中光学参数随着其值的增加出现频率降低。0-2km高度层内大气散射能力强于其他高度空间,532nm后向散射系数峰值主要在0.0008-0.0025km-1·sr-1范围内；体积退偏振比以0-15%为主；色比频率随着取值的增大呈现先增大后减小的变化规律,频率峰值出现在0.4-1.0之间。气溶胶具有吸湿性,湿霾天气时气溶胶吸湿后下沉,边界层散射强度减弱,以中等粒径且表面规则的气溶胶颗粒物为主。中层由于气溶胶颗粒物吸湿后表面较为且则粒径增大,散射能力增强。高层空间由于空气相对干燥,干霾和湿霾时大气结构变化较小。比较不同程度霾过程,轻度霾时以较规则的细粒子气溶胶为主,中度霾时以规则的粗粒子气溶胶为主,重度霾时以不规则细粒子气溶胶为主。 (3)利用CALIOP激光雷达数据进行杭州市区霾探测研究：根据三个参数的F检验结果,结合不同天气过程时市区大气参数的垂直分布特征,利用0.5-1.2km高度层内的光学参数对霾过程进行判识。SPSS判别运算结果表明,以VDR/BKS/COR(各高度依次排列)的组合方式建立判别函数可以有效的区分无霾与霾天。根据修正后的消光系数计算垂直能见度,进而得到霾层厚度,有利于加深对霾过程气溶胶分布的正确认识。 (4)杭州市区霾源分析：结合地面气象资料、主要大气污染物质量浓度情况与CALIOP激光雷达数据,对2013年1月26日霾过程进行案例分析。结果表明,当日霾层厚度在1km左右,污染物主要集中在近地面；霾天气的发生,除了受到静风、逆温以及连续多日无降水等气象影响外。汽车尾气等本地污染物的不断积累也为霾的产生提供了有利条件。HYSPLIT轨迹反演结果表明气流传输带来的外部污染物在一定程度上降低了大气能见度,促进了霾天气的出现。因此对于霾的控制与治理不但需要控制本地污染物的产生和排放,区域联合治理也是重要控制手段。
[Abstract]:With the development of China's economy and the progress of urbanization, low visibility weather has become an important environmental problem in many cities in China. Haze has also been upgraded from the original weather condition to a pollution phenomenon. The current observation of haze mainly depends on the ground observation stations and optical remote sensing to provide air quality and haze pollution range. The detection of atmospheric aerosol vertical distribution in haze days is relatively small. The "cloud aerosol laser radar infrared Blazers (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations, CALIPSO)" launched by the National Aeronautics and Space Administration (NASA) and the National Space Center of France (CNES) in 2006 provides higher vertical resolution. The global cloud and aerosol observation data of the measurement accuracy provide an effective monitoring means for studying the vertical distribution characteristics of atmospheric aerosols in haze process.
Based on the meteorological data of 7 conventional meteorological stations in Hangzhou and the data of the air pollution index, the historical evolution of haze weather in Hangzhou and the seasonal and monthly changes of haze weather in Hangzhou are studied according to the haze observation and prediction grade (QX/T113-2010) standard, and the Hangzhou urban area is analyzed by the satellite borne lidar data. Based on the atmospheric vertical structure characteristics of haze and haze days, the method of detecting Urban Haze based on spaceborne lidar is obtained. The following 4 conclusions are drawn:
(1) the characteristics of the time evolution of haze weather in Hangzhou City:
The historical evolution process of haze days in Hangzhou in 1951 can be divided into 3 stages: the environmental recovery period of 1951-1964 years, the stable period of 1965-1975 years and the rapid growth period of the haze day days after 1975. The seasonal changes of the days of haze days are: winter spring and autumn summer, this is mainly influenced by the climate conditions of Hangzhou. The characteristics are: haze processes are most likely to occur in January and December, and the average annual occurrence of haze in July is the least.
(2) the characteristics of atmospheric vertical distribution in Hangzhou City:
As the height increases, the values of the atmospheric backscattering coefficient, the volume depolarization ratio and the color ratio are reduced, and the irregularity of the aerosol is weakened. The optical parameters in the height layers decrease with their values and the atmospheric scattering ability in the.0-2km height layer is stronger than that in his high altitude, and the peak backscattering coefficient of the 532nm is the main peak. In the range of 0.0008-0.0025km-1 SR-1, the volume depolarization ratio is mainly 0-15%, and the frequency of color ratio increases first and then decreases with the increase of value, and the peak frequency occurs between 0.4-1.0.
The aerosol is hygroscopic, the aerosol is wet after wet haze, the scattering intensity of the boundary layer is weakened, and the medium particle size and surface rule aerosol particles are the main. The middle layer is larger and the particle size increases after the aerosol particles are hygroscopic and the scattering ability is enhanced. The high rise space is due to the dry air, dry haze and haze. The change of gas structure is small. Compared to different degree haze process, the regular fine aerosol aerosol is the main type of light haze, and the regular coarse particle aerosol is the dominant aerosol in moderate haze, and the heavy haze is dominated by irregular fine particle aerosol.
(3) using CALIOP lidar data to detect haze in Hangzhou:
According to the results of the F test of three parameters and the vertical distribution characteristics of the urban atmospheric parameters in different weather processes, the result of identifying the haze process by the optical parameters in the 0.5-1.2km height layer shows that the discriminant function of the combination mode of VDR/BKS/COR (each height arranged in order) can effectively distinguish the haze from the haze. Based on the corrected extinction coefficient, the vertical visibility is obtained, and the thickness of the haze layer is obtained, which is helpful to deepen the correct understanding of the aerosol distribution in haze process.
(4) analysis of haze sources in Hangzhou City:
Based on the ground meteorological data, the mass concentration of air pollutants and the data of CALIOP lidar, the haze process in January 26, 2013 is analyzed. The results show that the thickness of the haze layer is around 1km, and the pollutants are mainly concentrated in the near ground, and the occurrence of haze weather is not only subjected to static wind, inversion, and no precipitation for many days. The continuous accumulation of local pollutants, such as automobile exhaust, also provides favorable conditions for the production of haze..HYSPLIT trajectory inversion results show that the external pollutants brought by the air flow can reduce the visibility of the atmosphere to a certain extent and promote the appearance of haze weather. Therefore, the control and control of haze not only need to control the local pollutants. Regional joint governance is also an important means of control.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X831;TN958.98

【参考文献】