基于激光雷达的南京仙林地区气溶胶遥感监测研究

发布时间：2018-07-01 11:32

本文选题：激光雷达 + 气溶胶监测　；参考：《南京师范大学》2015年硕士论文

【摘要】：激光雷达以其高时间和垂直空间分辨率的特点在大气气溶胶监测中发挥着日益重要的作用。本文选择南京仙林地区为实验区,通过优化雷达反演过程中的重要参数(雷达比),提高激光雷达反演精度的影响。利用雷达反演结果分析了2014年3月至2015年2月南京仙林地区上空气溶胶的时空变化情况,并结合多源数据对2014年5月26日至6月1日研究区一次典型大气气溶胶污染过程进行了评价分析。主要研究成果体现在以下几个方面：(1)基于能见度的动态雷达比计算方法。雷达比是影响激光雷达反演精度的重要因素之一,本文提出了一种利用能见度换算的近地表消光系数作为激光雷达反演约束进而解算出雷达比的方法。与传统方法相比,该方法求得了在更小时间尺度上连续的雷达比动态变化情况。实验表明：利用动态雷达比能明显提高激光雷达反演精度。(2)激光雷达可以有效探测气溶胶的垂直分层结构,这体现出了其对于大气污染监测的独特优势。利用激光雷达探测结果对南京仙林地区气溶胶光学特性垂直分布进行了分析。在观测期内,在近地表200m高度的消光系数明显较大,气溶胶浓度高。0-0.2km和0.2-0.5km两个高度的变化趋势基本一致,都呈现出双峰结构,这与地表人类活动密切相关。地表湍流使得0.5-1km高度的消光系数均值在午后出现上升且明显大于0.2-0.5km高度范围的消光系数均值。仙林地区的大气边界层在一日之内变化明显,观测期内平均波动范围在1-2km左右。边界层高度的变化主要和太阳辐射强度有关。观测期每个月份的消光系数平均廓线各有不同。2015年1月份的近地表消光系数均值最小,约为0.4kmm-1左右,最大值为2014年7月,约为0.7km-1左右。2014年9月、10月以及2015年2月的近地表月均值比较大,达到0.6km-1左右。此外,每个月都不同程度受到地表湍流影响,夏季地表温度较高,湍流影响最大。(3)由于激光雷达所获取的数据不具有面上的代表性且本文的单波段Mie散射雷达测量参数相对较少,仅靠单一设备很难实现对气溶胶污染过程的全面科学分析。因此,利用多源数据参与污染过程评价具有必要性。本研究基于激光雷达数据,结合气象资料、环境监测数据以及数值模拟结果(NAAPS、HYSPLIT)等多源数据对典型气溶胶污染案例进行分析。本次污染过程受到沙尘、秸秆以及本地排放的污染物叠加影响。这说明南京地区大气污染过程复杂且污染源多样,大气污染治理形势严峻。环境监测数据可以应用于污染过程的提取及不同阶段污染特征分析。数值模拟结果即能够呈现出污染物空间分布,也可以用于污染物来源分析。激光雷达反演结果可以清晰地反映出污染物的分布聚集情况以及时空变化。此外,气象资料对于大气气溶胶监测也具有重要的意义。一方面,气象要素影响着雷达比,进而影响到激光雷达反演精度；另一方面,在污染过程中,气象要素对污染过程的产生、发展以及终结都具有重要作用。低压、逆温等现象均不利于污染物的扩散,会加重大气污染,而降雨、大风等则有利于污染物的消散。
[Abstract]:Laser radar is playing an increasingly important role in atmospheric aerosol monitoring with its high time and vertical spatial resolution. This paper selects the Nanjing Xianlin area as the experimentation area. By optimizing the important parameters in the radar inversion process (radar ratio), the effect of the laser radar inversion accuracy is improved. The results of the radar inversion are analyzed by using the radar inversion results 2014. The spatio-temporal change of the air sol in Xianlin area, Nanjing, from March to February 2015, and the evaluation and analysis of a typical atmospheric aerosol pollution process in the study area from May 26, 2014 to June 1st, combined with multi source data. The main research results are reflected in the following aspects: (1) the dynamic radar ratio calculation method based on visibility. Dabby is one of the important factors affecting the precision of laser radar inversion. In this paper, a method of using the near surface extinction coefficient converted by visibility as a laser radar inversion constraint and then to calculate the radar ratio is proposed. Compared with the traditional method, the method obtains the dynamic change of the radar ratio at a smaller time scale. The results show that using dynamic radar ratio can obviously improve the inversion accuracy of laser radar. (2) laser radar can effectively detect the vertical stratified structure of aerosol, which shows its unique advantage for air pollution monitoring. Using laser radar detection results, the vertical distribution of optical properties of gas soluble gel in Nanjing Xianlin area is analyzed. During the period of time, the extinction coefficient at the height of the near surface 200m is obviously larger, the two height of.0-0.2km and 0.2-0.5km with high aerosol concentration are basically the same, all of which show the Shuangfeng structure, which is closely related to the human activities on the surface. The surface turbulence makes the mean of the extinction coefficient of the height of 0.5-1km rising in the afternoon and obviously greater than that of 0.2-0.5km The average fluctuation of the atmospheric boundary layer in the high range is obvious within one day, and the average fluctuation range is about 1-2km in the observation period. The change of the boundary layer height is mainly related to the solar radiation intensity. The average extinction coefficient of the extinction coefficient in each month of the observation period is different from the near surface extinction coefficient in the January of the.2015 year. The minimum value, about 0.4kmm-1, is about 0.4kmm-1, the maximum value is July 2014, about 0.7km-1.2014 September, October and February 2015, the average monthly mean value is about 0.6km-1. In addition, the surface turbulence is affected to different degrees in each month, the surface temperature is higher in summer and the turbulence has the greatest influence. (3) the data obtained by laser radar It does not have the representativeness on the surface and the single band Mie scattering radar has relatively few measurement parameters. It is difficult to realize the comprehensive scientific analysis of the process of aerosol pollution only on a single device. Therefore, it is necessary to use multi source data to participate in the evaluation of the pollution process. Typical aerosol pollution cases are analyzed by multi source data such as NAAPS (HYSPLIT). The pollution process is affected by the superposition of dust, straw and local pollutants. This shows that the atmosphere pollution process in Nanjing is complex and the pollution sources are diverse, the air pollution control situation is severe. The environmental monitoring data can be used. It is applied to the extraction of pollution process and the analysis of pollution characteristics at different stages. The numerical simulation results can show the spatial distribution of pollutants, and can also be used to analyze the source of pollutants. The results of the lidar inversion can clearly reflect the distribution and aggregation of pollutants and the spatio-temporal change. In addition, the meteorological data can be used to monitor the atmospheric aerosol. On the one hand, the meteorological factors affect the radar ratio, and then affect the accuracy of the lidar inversion. On the other hand, in the process of pollution, the meteorological elements play an important role in the production, development and end of the pollution process. Low pressure, inversion and other phenomena are not conducive to the diffusion of pollutants, which will aggravate the air pollution, Rain, wind and so on are beneficial to the elimination of pollutants.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X87

【参考文献】