利用激光雷达探测兰州地区沙尘和黑碳气溶胶的研究

发布时间：2018-01-16 12:14

本文关键词：利用激光雷达探测兰州地区沙尘和黑碳气溶胶的研究　出处：《兰州大学》2015年硕士论文　论文类型：学位论文

【摘要】：大气气溶胶通过其直接、间接和半直接效应对区域和全球气候都有重要影响。地处中国西北半干旱区的兰州市是一个受沙尘天气影响较多、空气污染较严重的工业城市,因此对这种典型地区的沙尘和黑碳气溶胶进行长期观测,分析其分布特征,对进一步研究该区域气候变化,具有重要的科学意义和应用价值。本文利用微脉冲激光雷达(CE370-2)在兰州的观测资料,分析一次持续时间较长的沙尘过程气溶胶的垂直分布和演变特征,结合多角度吸收光度计(MAAP5012)、偏振激光雷达(L2S-SMⅡ)观测资料,分析获得兰州地区采暖期黑碳气溶胶浓度的日变化、逐日变化和季节变化,以及采暖期气溶胶消光系数和退偏比的垂直分布等定量结果,为检验数值模式模拟能力,调整参数化方案,进一步提高模式模拟精度,提供有力的支撑。主要结果如下：(1)无沙尘个例分析表明,兰州市无沙尘条件下气溶胶主要集中在1.5km以下,激光雷达后向散射信号垂直剖面图与气溶胶垂直廓线结果对应较好。气溶胶光学厚度全天整体较小,最大值为0.85,全天波动较小,平均为0.42。(2)对2013年3月8日-2013年3月15日的沙尘过程气溶胶垂直分布的分析表明,气溶胶消光系数的变化与沙尘过程的发展能够很好的对应,激光雷达探测高度基本在3km以内,沙尘气溶胶整体分布在lkm以下,沙尘过境前光学厚度值较小,平均为0.8左右,沙尘过境,AOD值急剧增加,最大达到3.0,之后转为浮尘天气,AOD值自9日开始又有所降低,直至3月13日,这期间气溶胶AOD值呈波动变化,减小-增大-减小,最小达到了0.5,与气溶胶消光系数的波动变化基本一致。(3)分析同期SACOL榆中观测站温度、相对湿度的垂直廓线。在低层温度从270K左右随高度降低,500-1000m高度存在一个逆温,之后基本随高度呈降低的趋势,而相对湿度的变化具有波动性。沙尘初期,相对湿度在低层最大值可达40%以上,到了沙尘过程中后期,低层的相对湿度最大值为35%左右。此外,相对湿度垂直廓线与同期消光系数垂直廓线变化趋势比较相似。(4)利用多角度吸收光度计观测分析了采暖期黑碳气溶胶浓度日变化、逐日变化和季节变化,结果显示,2009年、2010年及两年平均冬季黑碳浓度日变化总体呈现双峰结构,且2009年、2010年及两年平均日变化的总体趋势一致,第一个峰值出现在10：00至12：00之间,2009年最高值达到3000ng/m3,第二个峰值出现在20：00至23：00之间,2010年最高值2900ng/m3,谷值都出现在18：00左右。黑碳气溶胶逐日变化呈U型分布。(5)对比分析SACOL榆中综合观测站与城市观测站同时期黑碳浓度日变化发现,榆中站和城市站黑碳浓度都呈现出双峰结构的变化特征,城市站黑碳浓度总体高于榆中站,且城市站黑碳浓度变化波动大,采暖期黑碳浓度高于非采暖期。(6)利用偏振激光雷达(L2S-SM Ⅱ)观测分析了采暖期气溶胶消光系数和退偏比的垂直分布以及期间光学厚度的时间演变。兰州远郊采暖期气溶胶主要分布在2km以下,在低层1064nm的消光系数大于532nm的消光系数,反映了低层颗粒的粒径较大,污染型粒子的退偏比基本小于0.2,退偏比超过0.2的可能为沙尘粒子。(7)2009年采暖期光学厚度平均值为0.4,比采暖前期增加了60%；2010年采暖期光学厚度平均值为0.32,增加了23%；2011年采暖期光学厚度平均值为1.1,采暖前期光学厚度平均值为0.3,增加了200%多,说明人为源气溶胶在采暖期占主导作用。
[Abstract]:The atmospheric aerosol through the direct, indirect and semi direct effects have important influence on regional and global climate. Chinese located in semiarid region in the northwest of the city of Lanzhou is a lot under the influence of sand dust weather, air pollution is serious in the industrial city, so the long-term observation of the typical area of the sand dust and black carbon aerosol. Analysis of the distribution characteristics, for further research on the regional climate change has important scientific significance and application value. This paper using micro pulse lidar (CE370-2) in the observation data of Lanzhou, the vertical distribution and evolution characteristics of dust aerosol process analysis of a longer duration, combined with multi angle absorption spectrophotometer (MAAP5012). Polarized laser radar (L2S-SM II) observation data, analysis on the change of black carbon aerosol concentration during the heating period in Lanzhou area, daily and seasonal changes, and the heating period of aerosol fire The optical coefficients and the depolarization ratio of the vertical distribution of quantitative results, to test the ability of numerical simulation, adjust the parameters of the program, to further improve the model simulation accuracy, and provide strong support. The main results are as follows: (1) case analysis shows that no dust, no dust aerosol conditions in Lanzhou city focused on the following 1.5km, laser radar backscatter vertical profiles and aerosol vertical profile results correspond well. The aerosol optical thickness all day long overall smaller, the maximum value is 0.85, all day long small fluctuations, the average is 0.42. (2) analysis of the vertical distribution of dust aerosol process on March 8, 2013 -2013 in March 15th showed that the development and changes of the aerosol extinction coefficient and dust process can good correspondence, the lidar height is less than 3km, the overall distribution of dust aerosol under LKM, dust before crossing the optical thickness is smaller, the average About 0.8, dust transit, AOD value increased sharply, up to 3, after the turn to dust weather, AOD value since 9 day and then decreased, until March 13th, during which the aerosol AOD value fluctuated, decreasing increasing decreasing, the minimum reached 0.5, and the variation of aerosol extinction coefficient is basically the same over the same period. (3) analysis SACOL Yuzhong station temperature, vertical profiles of relative humidity. In the lower temperature from about 270K decrease with height, 500-1000m height is a basic inversion, with height was decreased, and the change of relative humidity is fluctuant. The dust early, relative humidity in low level the maximum value is more than 40%, to the late dust process, the maximum relative humidity in low level is about 35%. In addition, the relative humidity profiles compared with the extinction coefficient profiles change trend is similar. (4) using multi angle absorption photometer Observation and analysis of the variation of black carbon aerosol concentration, heating period, daily and seasonal changes, results show that in 2009 2010, and the average winter diurnal variation of black carbon concentration shows the structure of Shuangfeng, and in 2009, the overall trend of average daily change in 2010 and two years, the first peak is between 10:00 and 12:00, the highest in 2009 the value reached 3000ng/m3, the second peak appeared between 20:00 to 23:00 in 2010, the highest value of 2900ng/m3, the valley value appeared at about 18:00. The daily variation of black carbon aerosol was U distribution. (5) comparative analysis of comprehensive observation station and Yuzhong city SACOL stations at the same time the diurnal variation of the concentration of black carbon, black carbon concentration in Yuzhong station and city stations are showing the variation characteristics of Shuangfeng city station structure, black carbon concentration is higher than that of the Yuzhong station, and city station fluctuation of black carbon concentration, black carbon concentration is higher than the heating period The non heating period. (6) using a polarized laser radar (L2S-SM II) are observed and analyzed during the heating period of the aerosol extinction coefficient and depolarization ratio of vertical distribution and the optical thickness of the time evolution. During the heating period in Lanzhou aerosols mainly distributed in the 2km below is greater than the extinction coefficient 532nm in the number of low layer 1064nm extinction, reflect the lower layer of the larger granule size, the type of pollution particle depolarization ratio is less than 0.2 and the depolarization ratio of more than 0.2 for dust particles. (7) the optical thickness of the heating period in 2009 an average of 0.4, an increase of more than 60% pre heating heating period in 2010; the optical thickness of the average value is 0.32, an increase of 23% the heating period in 2011; the optical thickness of the average value is 1.1, pre heating the optical thickness of the average value is 0.3, an increase of more than 200%, indicating anthropogenic aerosol is dominant in the heating period.

【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P412.2;X87

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