A review of measurement-based assessments of the aerosol direct radiative effect and forcing

作者：Hongbin Yu, Yoram J. Kaufman, Mian Chin, Graham Feingold, Lorraine A. Remer, Theodore L. Anderson, Yves J. Balkanski, Nicolas Bellouin, Oliviér Boucher, S. Christopher, Philip L. DeCola, Ralph A. Kahn, Dorothy M. Koch, Norman G. Loeb, M. Shekar Reddy, Michael Schulz, Toshihiko Takemura, Mi Zhou · 发表于：Atmospheric chemistry and physics · 年份：2006 · DOI：10.5194/acp-6-613-2006 · 被引用次数：919 · 研究领域：Atmospheric aerosols and clouds、Atmospheric chemistry and aerosols、Atmospheric Ozone and Climate

Abstract. Aerosols affect the Earth's energy budget directly by scattering and absorbing radiation and indirectly by acting as cloud condensation nuclei and, thereby, affecting cloud properties. However, large uncertainties exist in current estimates of aerosol forcing because of incomplete knowledge concerning the distribution and the physical and chemical properties of aerosols as well as aerosol-cloud interactions. In recent years, a great deal of effort has gone into improving measurements and datasets. It is thus feasible to shift the estimates of aerosol forcing from largely model-based to increasingly measurement-based. Our goal is to assess current observational capabilities and identify uncertainties in the aerosol direct forcing through comparisons of different methods with independent sources of uncertainties. Here we assess the aerosol optical depth (τ), direct radiative effect (DRE) by natural and anthropogenic aerosols, and direct climate forcing (DCF) by anthropogenic aerosols, focusing on satellite and ground-based measurements supplemented by global chemical transport model (CTM) simulations. The multi-spectral MODIS measures global distributions of aerosol optical depth (τ) on a daily scale, with a high accuracy of ±0.03±0.05τ over ocean. The annual average τ is about 0.14 over global ocean, of which about 21%±7% is contributed by human activities, as estimated by MODIS fine-mode fraction. The multi-angle MISR derives an annual average AOD of 0.23 over globa...