Effects of absorbing aerosols in cloudy skies: a satellite study over the Atlantic Ocean
Effects of absorbing aerosols in cloudy skies: a satellite study over the Atlantic Ocean
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DOI：
10.5194/acp-11-1393-2011
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发表时间：
2009-10
影响因子：
6.3
通讯作者：
K. Peters;J. Quaas;N. Bellouin
中科院分区：
文献类型：
--
作者：
K. Peters;J. Quaas;N. Bellouin
摘要。我们提出了一种仅从卫星资料中推导在多云场景中吸收气溶胶的辐射效应的方法。我们使用了“A-Train”星座卫星上各种无源传感器2005-2007年的数据。研究区域仅限于热带和亚热带大西洋。为了确定多云场景下的行星反照率与云液态水路径和气溶胶光学深度（AOD）的关系，我们进行了多元线性回归。OMI紫外线气溶胶指数作为吸收气溶胶存在的指标。在我们的方法中，气溶胶通过直接（散射和吸收）和间接（Twomey）气溶胶效应影响局部行星反照率。结果表明，随着主要散射气溶胶AOD的增加，局地行星反照率增加；随着主要吸收气溶胶AOD的增加，局地行星反照率降低。这些结果使我们能够得出在多云场景中吸收气溶胶的直接气溶胶效应，其中热带和亚热带大西洋的多云场景气溶胶吸收对全球大气辐射强迫的贡献为（+21.2±11.1）×10−3 Wm−2。
Abstract. We present a method for deriving the radiative effects of absorbing aerosols in cloudy scenes from satellite retrievals only. We use data of 2005–2007 from various passive sensors aboard satellites of the "A-Train" constellation. The study area is restricted to the tropical- and subtropical Atlantic Ocean. To identify the dependence of the local planetary albedo in cloudy scenes on cloud liquid water path and aerosol optical depth (AOD), we perform a multiple linear regression. The OMI UV-Aerosolindex serves as an indicator for absorbing-aerosol presence. In our method, the aerosol influences the local planetary albedo through direct- (scattering and absorption) and indirect (Twomey) aerosol effects. We find an increase of the local planetary albedo (LPA) with increasing AOD of mostly scattering aerosol and a decrease of the LPA with increasing AOD of mostly absorbing aerosol. These results allow us to derive the direct aerosol effect of absorbing aerosols in cloudy scenes, with the effect of cloudy-scene aerosol absorption in the tropical- and subtropical Atlantic contributing (+21.2 ± 11.1)×10 −3 Wm −2 to the global top of the atmosphere radiative forcing.