| 北京不同污染事件期间气溶胶光学特性 |
| 摘要点击 3208 全文点击 1675 投稿时间：2013-02-23 修订日期：2013-05-17 |
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| 中文关键词 气溶胶 光学特性 秸秆焚烧 烟花 沙尘 北京 |
| 英文关键词 aerosol optical properties biomass burning firework dust Beijing |
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| 中文摘要 |
| 利用2005~2011年的AERONET观测数据,对北京不同污染事件期间(秸秆焚烧、烟花燃放以及沙尘天气)气溶胶光学特性进行了分析. 气溶胶光学厚度受污染有显著上升,沙尘、秸秆、烟花气溶胶的AOD440 nm分别是干净背景的4.91、4.07、2.65倍. AOD与Ångström波长指数的匹配能够较好地识别污染类型,沙尘对应高AOD和低α,烟花气溶胶α(1.09)稍低于秸秆(1.21)以及背景(1.27),表明烟花气溶胶的粗粒子更占优,秸秆对应更高的AOD则与其中黑碳颗粒较强的消光能力有关. 单次散射反照率对波长敏感性不高,沙尘气溶胶的ω值(0.934)高于背景值(0.878)、秸秆气溶胶(0.921)以及烟花气溶胶(0.905),秸秆气溶胶受烟羽老化、吸湿性增长等影响表现出偏大现象. 气溶胶粒子谱分布在背景与污染期间均为双峰模态,细模态和粗模态的峰值浓度半径分别为0.1~0.2 μm以及2.24~3.85 μm,粗细粒子浓度比值由小到大依次为背景(1.04)、秸秆焚烧(1.10)、烟花燃放(1.91)以及沙尘气溶胶(4.96). |
| 英文摘要 |
| Based on the 2005-2011 data from Aerosol Robotic Network (AERONET), this study conducted analysis on aerosol optical properties over Beijing during different air-pollution episodes (biomass burning, CNY firework, dust storm). The aerosol optical depth (AOD) showed notable increases in the air-pollution episodes while the AOD (at 440 nm) during dust storm was 4.91, 4.07 and 2.65 times higher as background, biomass burning and firework aerosols. AOD along with Ångström exponent (α) can be used to determine the aerosol types. The dust aerosol had the highest AOD and the lowest α. The α value of firework (1.09) was smaller than biomass burning (1.21) and background (1.27), indicating that coarse particles were dominant in the former type. Higher AOD of burnings (than background) can be attributed to the optical extinction capability of black carbon aerosol. The single scattering albedo (SSA) was insensitive to wavelength. The SSA value of dust (0.934) was higher than background (0.878), biomass burning (0.921) and firework (0.905). Additionally, the extremely large SSA of burnings here maybe was caused by the aging smoke, hygroscopic growth and so on. The peak radius of aerosol volume size distributions were 0.1-0.2 μm and 2.24-3.85 μm in clear and polluted conditions. The value of volume concentration ratio between coarse and fine particles was in the order of clear background (1.04), biomass burning (1.10), CNY firework (1.91) and dust storm (4.96) episode. |
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