Based on the data of CE-318 sunphotometer at Tianjin boundary layer station from 2013 to 2014, the distribution characteristics of aerosol optical depth and ?ngstr?m exponent were analyzed. The results showed that, the average value of the aerosol optical depth (AOD) under 440nm and 500nm spectral band were 0.99±0.34 and 0.87±0.30, respectively. The monthly average of AOD under 500nm was highest in June 2013 the value equal to 1.41±0.79 and lowest in November 2013 the value equal to 0.49±0.92. For the reason of sand and dust weather the ?ngstr?m exponent was lowest in spring which value equal to 0.85±0.32. For the reason of high temperature weather the ?ngstr?m exponent was highest in summer which value equal to 1.16±0.29.The urban-industrial aerosol was the dominant type in Tianjin by the analysis of the distribution characteristics of ?ngstr?m exponent. By the joint effect of fine mode and coarse mode aerosol, AOD was higher than 2in spring. By the main effect of fine mode aerosol, AOD was higher than 2in summer. And hygroscopic character of aerosol made AOD increased in summer. The situation of AOD higher than 2in winter also by the effect of fine mode aerosol but the partical size was larger than summer. In the condition of haze day the AOD and ?ngstr?m exponent were higher than dust day and non-pollution day which value were 1.41±0.68 and 1.17±0.29. In the condition of dust day the AOD was 0.99±0.62 and the ?ngstr?m exponent was 0.55±0.22 which was lower than haze day and non-pollution day. In condition of non-pollution day the AOD was lower than dust day and haze day which the value was 0.53±0.46. Increasing with AOD the ?ngstr?m exponent had trend of increased at first and decreased subsequently.%利用2013~2014年天津大气边界层观测站的CE318太阳光度计观测资料,分析天津气溶胶光学厚度(AOD)和波长指数(α)的分布特征.结果表明,天津地区AOD440nm和AOD500nm均值分别为0.99±0.34和0.87±0.30,波长500nm下AOD月均最高值为1.41±0.79,出现在2013年6月,最低值为0.49±0.92,出现在2013年11月.AOD的季节变化特征为春季受沙尘天气影响,α最低(0.85±0.32),夏季受高温天气条件影响,新生小粒子占比较多,α 最高(1.16±0.29),根据 α 分布特点,影响天津地区的主要气溶胶类型为城市—工业气溶胶.造成春季 AOD 高值(AOD≥2)情况出现是受粗、细模态气溶胶粒子共同影响,夏季 AOD 高值出现主要是受细模态粒子影响,同时细粒子吸湿增长特性对 AOD增长有较大影响.冬季 AOD 高值出现同样主要受细模态气溶胶粒子影响,其气溶胶粒子粒径高于夏季.对比沙尘、霾及非污染天气条件下AOD和α的差别,发现霾天气下AOD和α最高,分别为1.41±0.68和1.17±0.29,沙尘天气下AOD为0.99±0.62,α最低,为0.55±0.22.非污染天气下AOD最低,为0.53±0.46.不同天气条件下,随AOD增长α均有先升高后降低的特征.
展开▼
