武汉地区气象要素变化特征及其与污染物浓度影响分析

论文总字数：22477字

目 录

1. 引言 5

1.1 研究背景和意义 5

1.2 国内外研究进展 6

1.3 研究内容 7

2. 数据资料和方法 7

2.1 站点介绍 7

2.2 数据资料 7

2.3 研究方法 8

3. 结果分析 9

3.1. 最大边界层高度变化特征 9

3.1.1. 月、季节均值变化 9

3.1.2. 日均值变化 11

3.2. 逐日污染物浓度变化特征 12

3.2.1. 月、季均值变化 12

3.3. 边界层高度与污染物浓度的关系 13

3.4. 其他污染物浓度影响因素 15

3.4.1. 降水 15

3.4.2. 风速 17

3.4.3. 边界层高度响应能力 18

4. 讨论及结论 20

参考文献 21

致谢 25

武汉地区最大边界层高度变化特征及其

与污染物浓度影响分析

李嘉欣

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Abstract: In order to investigate the mechanism of the atmospheric boundary layer height (ABLH) parameters and meteorological factors on the pollution process, the dry isothermal method was applied to calculate the maximum height of the atmospheric boundary layer in Wuhan from 2013 to 2014. The effect on the concentration of PM_2.5 combined with wind speed and precipitation was analyzed simultaneously. The results showed that: 1) The maximum height of atmospheric boundary layer is the highest in summer, and the lowest in winter .The height is higher in spring than in autumn. Due to the effect of static weather, winter has the significantly smaller height variation. 2) The variation of ABLH is strongly influenced by solar radiation. Under different weather conditions, there is not much difference between sunny and cloudy conditions. The height in overcast conditions which is not conducive to the development of ABLH is nearly 400 m lower than the two others. 3) There is a significant negative correlation between the ABLH and the surface concentration of PM_2.5. The concentration of pollutants reaches to the highest when the ABLH is below 600m. As the ABLH increases, the concentration of pollutants decreases rapidly until the height exceeds 1400m,where the surface concentration of PM_2.5 decreases slightly. 4) The concentration of PM2.5 in the lower height of atmospheric boundary layer is more strongly affected by precipitation and windy weather. The effect of precipitation on the concentration of PM2.5 has two factors. The removal efficiency is negative in the condition that the precipitation is 0.1~1 mm and the pollution is aggravated; above 1 mm, the removal efficiency increases with the increase of precipitation. Besides, there is a significant negative correlation between wind speed and pollutant concentration. Under small wind conditions(lt;1.5m/s), the pollutant concentration reaches a high value of 0.3 mg/m³, and when the wind speed is above 3 m/s, the concentration of pollutants decreases drastically and is eventually consistent with the background concentration.

Key words: Maximum height of atmospheric boundary layer; Dry adiabatic method; PM2.5; Precipitation; Wind speed

1. 引言
   1. 研究背景和意义

自改革开放以来，随着经济的迅速发展和城市化进程的加快，以PM_2.5为首要污染物的霾天气现象迅速增加，据统计，2013年全国平均霾日数较2012年增加了近1倍^[1]，严重影响了人们的生产生活，大气环境污染问题现已成为科学界乃至全社会广泛关注的焦点问题。诸多学者已在雾霾的时空分布^[2]、成因^[3-4]和化学组成^[5-6]等方面开展了研究，包括气溶胶新粒子的形成^[7-9]、吸湿增长作用^[10-12]、气溶胶在环境大气中的转化过程^[13]、污染物浓度对气象条件的响应^[14]等等。研究^[15]表明，空气污染物散布的核心过程是大气扩散和输送过程，主要表现为垂直方向上的扩散和水平方向上的水平风输送，研究这一过程的变化不仅能对空气污染的有效防治提供重要的参考，同时在考虑经济效益的基础上，对提高城市空气质量具有重要的现实意义。但大气扩散稀释率的影响因子是复杂的，诸多大气扩散相关实验和研究^[16-18]表明，对于同一污染源排放，任意一点监测到的污染物浓度数值总是不断变化的，这种变化除了受污染物的源排放影响外，主要受气象条件的支配，不同气象条件下，同一单位源排放所监测到的污染物浓度不同。

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