| 北京雾霾天气期间气溶胶光学特性 |
| 摘要点击 4881 全文点击 2904 投稿时间：2011-06-30 修订日期：2011-09-13 |
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| 中文关键词 北京 雾 霾 气溶胶 光学特性 |
| 英文关键词 Beijing fog haze aerosol optical property |
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| 中文摘要 |
| 为了解北京地区雾霾天气条件下大气气溶胶的光学特性,利用2002~2008年AERONET资料分析了雾霾天气期间气溶胶光学厚度、Angstrom波长指数、粒子尺度谱分布和单次散射反照率等气溶胶光学特性参数.结果表明,北京地区雾霾天气期间气溶胶光学厚度表现出较高值,且随波长增大而减小,440 nm时平均气溶胶光学厚度达到1.34. Angstrom波长指数在雾霾天气时也表现出较高值,平均值达到1.11; 其中高于0.9的波长指数出现频率达到94%,说明北京雾霾天气期间气溶胶粒子主要以细粒子为主.气溶胶体积尺度谱分布表现出双峰型结构,细模态的平均峰值半径随光学厚度增大而增大,而粗模态的平均峰值半径却随光学厚度增大表现出减小趋势; 气溶胶粒子尺度谱中的主模态峰与光学厚度有关.雾霾天气期间平均单次散射反照率达到0.89,且随光学厚度增大表现出依次增大趋势,但对波长变化表现不敏感. |
| 英文摘要 |
| The purpose of this study is to investigate the optical properties of aerosol during haze-fog episodes in Beijing. The aerosol optical depth (AOD), Angstrom exponent (α), size distribution and single scattering albedo (ω) during haze-fog episodes were analyzed between 2002 and 2008 using AERONENT data. During haze-fog episodes, the aerosol optical depth showed a decreasing trend with wavelengths, and showed high values with an average 1.34 at 440 nm. The magnitude of Angstrom exponent was relatively high during haze-fog episodes and the mean values reached 1.11. The frequency distribution of α was up to 94% when α>0.9, indicating the predominance of fine particles during haze-fog episodes in Beijing. The aerosol volume size distributions presented a bimodal structure (fine and coarse modes). The maxima (peaks) radius of fine mode showed an increasing trend with AOD, however, those of coarse mode showed a decreasing trend with AOD. The size distribution showed a distinct difference in dominant mode for the different AOD. The single scattering albedo showed an increasing trend with AOD during haze-fog episodes in Beijing. The mean value of ω was 0.89 at the four wavelengths and the ω exhibited a low sensitivity to wavelengths. |
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