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Britton B. Stephens, Peter S. Bakwin, Pieter P. Tans, Ron M. Teclaw, and Daniel D. Baumann

layer to the interior of continents, and to apply these continental measurements to study global CO 2 budgeting, terrestrial biospheric processes, atmospheric transport, and industrial emissions. Presently, observed trends in atmospheric O 2 provide our best constraint on the long-term global partitioning of terrestrial and oceanic sinks for anthropogenic CO 2 ( Houghton et al. 2001 ). A key value in calculating this partitioning is the assumed O 2 :CO 2 ratio for the terrestrial uptake of

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Andrew R. Jongeward, Zhanqing Li, Hao He, and Xiaoxiong Xiong

attribution more reliably than any single source can suggest where the strengths of one data type can augment the deficiencies of others. This work expands on previous studies by considering the anthropogenic effects downwind of any significant anthropogenic sources. This paper is presented as follows. Section 2 describes the data products employed for this work. Section 3 contains results of AOD trend analysis from satellite and surface observational datasets. Section 4 discusses the attribution of

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Bjorn Stevens and Stephanie Fiedler

estimate the anthropogenic aerosol burden at different time periods, following methods developed in S15 . That is, we calculate the difference in the reflected clear-sky shortwave irradiance, over the ocean, between a given period and a preindustrial period, here taken to be a period between 1861 and 1869 with relatively little volcanic activity. To minimize possible effects from residual volcanic aerosol, and similar to S15 , we next calculate the anomaly in this quantity relative to the lowest

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Lawrence C. Hamilton and Mary D. Stampone

climate. Even education and science literacy have divergent effects, depending on politics ( Hamilton 2008 , 2011b , 2012 ; Hamilton et al. 2012 ; Kahan et al. 2011a , b ; McCright 2011 ; McCright and Dunlap 2011 ). Among self-identified Democrats or liberals, higher education and science literacy are associated with greater concern regarding anthropogenic climate change. Among Republicans or conservatives, education and science literacy have weak or even negative effects. Among unaligned

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Lu Dong and Tianjun Zhou

have contributions in some modeling studies. The ocean temperature advection is regarded as the dominant process for the increase of the northern Indian Ocean heat content, while surface heat fluxes prevail in other areas of the Indian Ocean basin ( Barnett et al. 2005 ). In addition to GHGs, aerosols probably exert the second largest anthropogenic radiative forcing of the climate ( Solomon et al. 2007 , 200–205; Mitchell et al. 1995 ), especially the effects of black carbon, sulfate aerosols, and

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Edwin P. Gerber and Seok-Woo Son

the gross thermodynamic response of the atmosphere to anthropogenic forcing, models would not agree on the circulation response. To differentiate this source of uncertainty from the impact of climate sensitivity, we term this source of model spread a “circulation sensitivity.” Our framework suggests that these differences in the large-scale circulation response contribute equally to intermodel spread as differences in the thermal forcing. We detail the datasets and develop our simple attribution

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Minjoong J. Kim, Sang-Wook Yeh, Rokjin J. Park, Seok-Woo Son, Byung-Kwon Moon, Byung-Gon Kim, Jae-Jin Kim, and Sang-Woo Kim

2 run (Gg S yr −1 ), (b) sulfate concentration at surface ( μ g m −3 yr −1 ), and (c) sulfate aerosol optical depth (yr −1 ). Shading denotes a statistically significant region at the 90% confidence level. Three CAM5 model experiments were performed to isolate the effects of anthropogenic sulfate aerosol emissions in China on regional Arctic amplification. The first experiment prescribed a historical SST and sea ice from 1985 to 2010 (i.e., 26 years) without SO 2 (a precursor gas of sulfate

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Maria M. Kvalevåg and Gunnar Myhre

brightening are functions of changes in the sum of direct and diffuse (scattered light) surface solar radiation. Therefore, it is important to quantify the changes in the direct and diffuse solar radiation throughout the industrial era up to the present, as well as to better understand the mechanisms behind them. One factor that might explain change in surface solar radiation is the presence of clouds, due to their large variability and the extent to which they are influenced by anthropogenic aerosols

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Robert K. Kaufmann, Karen C. Seto, Annemarie Schneider, Zouting Liu, Liming Zhou, and Weile Wang

surface areas.” This implies that anthropogenic changes in land use could have significant effects on local precipitation throughout the world. Acknowledgments This research was supported by the U.S. National Science Foundation, CAREER Program, Grant BCS-348986 (Seto). REFERENCES Arnfield , A. J. , 2003 : Two decades of urban climate research: A review of turbulence, exchanges of energy and water, and the urban heat island. Int. J. Climatol. , 23 , 1 – 26 . Arthur-Hartranft , T. , N

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Martin Hoerling, Jon Eischeid, and Judith Perlwitz

discount the role of other effects that anthropogenic climate forcings (i.e., aerosols via their direct and indirect effects) included in the CMIP simulations can exert on regional precipitation changes (e.g., Ming and Ramaswamy 2009 ). We are, however, reasonably assured that the AMIP ensemble precipitation trends offer a realistic diagnosis of the role of SSTs in the fully coupled observed system during 1977–2006, and that they also provide insight into the causes for rainfall trends in the CMIP

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