京津冀大气混合层高度变化特征及其与细颗粒污染物的关系研究

发布时间：2018-01-03 06:12

本文关键词：京津冀大气混合层高度变化特征及其与细颗粒污染物的关系研究　出处：《南京信息工程大学》2015年硕士论文　论文类型：学位论文

【摘要】：大气混合层高度(Mixing Layer Height,简写为MLH)是影响大气扩散的主要因子之一,其对大气质量评估和污染物的存储量及分布起着重要作用。本实验利用云高仪对2013年10月16日至2014年10月15日京津冀区域4个站点(北京、天津、石家庄和秦皇岛)MLH进行了同步连续观测,分析了其各自及其区域总体变化特性。结果表明：北京MLH年均值最高,为688±250m；天津次之,为597±219m;秦皇岛和石家庄较低,分别为444±180m和547±257m。但季节变化有所不同,MLH按从大到小顺序排列,在春季依次是北京站、天津站、石家庄站、秦皇岛站,值分别为816、637、606、448；夏季依次北京、石家庄、天津、秦皇岛,值分别为832、748、681、381；秋季依次北京、天津、石家庄、秦皇岛,值分别为556、555、510、472；冬季依次是北京、天津、秦皇岛、石家庄,值分别为555、519、492、378.石家庄MLH的位置变化,局地温度变化是主因,近地层高浓度污染对混合层高度也可能存在负反馈。北京、天津和石家庄在由春转夏时,MLH各自都有不同程度的升高；由夏季转秋季时, MLH又有不同幅度的降低；冬季均为一年中的最低值。秦皇岛夏季MLH出现明显低值,381±133m,其它季节的MLH维持在465+205m。所有城市MLH统计日变化均呈现白天高、夜晚低的单峰型日变化形式,昼夜变化幅度显著；而秦皇岛夏季全天MLH统计日变化均低于其它3个城市,昼夜变幅最小。区域内4城市混合层高度和结构的变化均有典型的局地特征。结合气象数据分析发现,北京、天津和石家庄白天大气混合层高度受到热浮升力的作用明显,到了晚上,秦皇岛和天津受海风作用增强,而石家庄和北京风速小、湍流作用不明显。气温的变化对天津、北京和石家庄地区MLH的季节变化有着重要的作用,而盛行风的变化对秦皇岛地区的MLH的季节变化有重要作用。结合PM2.5数据发现,所有站点大气细颗粒物浓度均随混合层高度的下降而升高,但站点间存在显著性差异；石家庄和天津这种相反的变化趋势更明显,而北京和秦皇岛则不明显。本文将质量浓度乘以MLH代表4个城市大气细颗粒物的污染负荷(PM2.5×MLH)结果表明：石家庄、北京和天津3个站点在春夏两季时,机动排放源对各自的地区贡献较大,但是到了秋冬季节时,北京白天受机动车(汽车)排放源的影响相对减弱而夜间受柴油车的影响依然显著。石家庄因为不利的扩散条件使得近地面细颗粒物浓度积累,尤其高架源对其PM2.5贡献显著；虽然天津PM2.5污染早、晚交通高峰出现高值,但大气污染负荷中午前后到达最大,说明天津大气污染受机动车和燃煤双重影响；由于受海-陆风震荡清洗的作用,秦皇岛全年大气污染负荷较低,无法有效识别局地污染排放对PM2.5的贡献。北京、天津、石家庄和秦皇岛大气MLH均呈现白天高、夜晚低的共性,但其季节变化又有其各自特点,影响MLH变化的气象要素也不尽相同；各城市影响大气污染负荷程度的要素有显著差别。石家庄冬季受高架点源影响显著,北京夜间受柴油车影响突出,天津则显示受机动车和燃煤双重影响,秦皇岛则难以使用本研究方法判别。研究结果对于认知京津冀区域污染分布现状具有重要意义,并可为区域内污染源合理调控提供科学参考。
[Abstract]:Atmospheric mixing height (Mixing Layer Height, abbreviated as MLH) is one of the main factors affecting atmospheric diffusion, the atmospheric quality assessment and pollutant storage and distribution plays an important role. This experiment using ceilometer for the October 16, 2013 to October 15, 2014 the Beijing Tianjin Hebei region 4 sites (Beijing, Tianjin, Shijiazhuang and Qinhuangdao) MLH the synchronization of continuous observation, analysis of their respective characteristics and overall regional changes. The results showed that: MLH in Beijing the highest mean was 688 + 250m; Tianjin, 597 + 219M; Qinhuangdao and Shijiazhuang is relatively low, were 444 + 180m and 547 + 257m., but the seasonal variation is different, according to the arrangement from the MLH to order in the spring, followed by the Beijing Railway Station, TianJin Railway Station, Shijiazhuang Railway Station, QinHuangDao Railway Station, respectively 816637606448; followed by Shijiazhuang, Beijing summer, Tianjin, Qinhuangdao, respectively 832748681381; The fall of Tianjin, Shijiazhuang, followed by Beijing, Qinhuangdao, respectively 556555510472; winter followed by Beijing, Tianjin, Qinhuangdao, Shijiazhuang, respectively to change the position of 555519492378. of Shijiazhuang's MLH, the local temperature change is the main reason that the surface layer of the mixed layer height the concentration of pollution may also exist negative feedback. Beijing, Tianjin and Shijiazhuang in the spring to summer, MLH each have increased to different extent; by the summer to autumn, and MLH were lower in winter; were the lowest value in a year. Qinhuangdao summer MLH appeared low value, 381 + 133m, the rest of the season MLH maintained at 465+205m. MLH all City Statistics showed diurnal variation during the day, the single peak diurnal variation form of night low, diurnal variation significantly; and the Qinhuangdao summer all day long MLH statistical diurnal variation were lower than those of the other 3 city, day and night minimum amplitude region 4 city. Local features have the typical structure of the mixed layer height and change. Based on the meteorological data analysis found that Beijing, Tianjin and Shijiazhuang during the daytime atmospheric mixed layer height by thermal buoyancy effect, at night, Qinhuangdao and Tianjin by the sea breeze effect is enhanced, while Shijiazhuang and Beijing wind speed, turbulence effect is not obvious. The change of temperature in Tianjin, plays an important role in the seasonal variation of MLH in Shijiazhuang and Beijing, have an important role in seasonal changes and the prevailing winds in the Qinhuangdao area of MLH. Combining with PM2.5 data found that all sites of airborne fine particulate matter concentration increased with the height of the mixed layer increases, but there were significant differences between sites Shijiazhuang and Tianjin; change the opposite trend is more obvious, while Beijing and Qinhuangdao are not obvious. The concentration multiplied by MLH on behalf of the 4 city atmospheric fine particles pollution Load (PM2.5 * MLH) the results showed that Shijiazhuang, Beijing and Tianjin 3 stations in summer two season, mobile emission sources contribute to their respective areas, but in the autumn season, Beijing day by motor vehicles (cars) influence the relative weakening of emission sources and night affected by diesel vehicles are still significant in Shijiazhuang. Because of the proliferation of adverse conditions makes the near surface concentrations of fine particulate matter accumulation, especially with elevated source of PM2.5 is significant; although Tianjin PM2.5 pollution early, late peak traffic high value, but the atmospheric pollution load reaches the maximum at noon, Tianjin air pollution by motor vehicles and coal-fired double impact; due to the effect by sea breeze vibration cleaning the air pollution load throughout the year in Qinhuangdao is relatively low, can not effectively identify local pollution emissions contribute to PM2.5. Beijing, Tianjin, Shijiazhuang and Qinhuangdao atmospheric MLH appears white night sky. Low in common, but the seasonal variation has its own characteristics, the influence of meteorological factors on variation of MLH are not the same; there was a significant difference between the various elements of city air pollution impact load. Shijiazhuang in winter by the elevated point source of Beijing at night by diesel effect prominent, Tianjin shows by motor vehicles and coal-fired double effect Qinhuangdao, is difficult to use the research on the identification method. The results have important significance for the cognition of Beijing Tianjin Hebei region pollution distribution status, and provide a scientific reference for regional pollution source reasonable regulation.

【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】：2015
【分类号】：X513

【参考文献】