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Yi Ming and V. Ramaswamy

. 2009 ), amount to a global mean of −2.1 W m −2 . The indirect effects account for 74% of the total aerosol forcing. Like the atmospheric burdens of anthropogenic aerosols, their radiative effects are located predominantly over the NH source regions. Refer to MR09 for a more detailed description of the model configuration and design of the experiments. Table 1 lists the tropical-mean changes in T , P , and M c due to different perturbations. Note that the tropics are defined as 30°S–30°N in

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Yang Chen, Wei Li, Xiaoling Jiang, Panmao Zhai, and Yali Luo

://doi.org/10.1029/2018EF001001 . 10.1029/2018EF001001 Li , C. , and Coauthors , 2019b : Larger increases in more extreme local precipitation events as climate warms . Geophys. Res. Lett. , 46 , 6885 – 6891 , https://doi.org/10.1029/2019GL082908 . 10.1029/2019GL082908 Li , H. X. , H. P. Chen , and H. J. Wang , 2017 : Effects of anthropogenic activity emerging as intensified extreme precipitation over China . J. Geophys. Res. Atmos. , 122 , 6899 – 6914 , https://doi.org/10.1002/2016JD

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Wei Chen, Buwen Dong, Laura Wilcox, Feifei Luo, Nick Dunstone, and Eleanor J. Highwood

. , T. B. Zhao , and K. R. Ying , 2015 : Effects of anthropogenic aerosols on temperature changes in China during the twentieth century based on CMIP5 models . Theor. Appl. Climatol. , 125 , 529 – 540 , https://doi.org/10.1007/s00704-015-1527-6 . 10.1007/s00704-015-1527-6 Li , Z. , and Coauthors , 2016 : Comparison of two homogenized datasets of daily maximum/mean/minimum temperature in China during 1960–2013 . J. Meteor. Res. , 30 , 53 – 66 , https://doi.org/10.1007/s13351

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Gerald A. Meehl, Warren M. Washington, Julie M. Arblaster, Aixue Hu, Haiyan Teng, Claudia Tebaldi, Benjamin N. Sanderson, Jean-Francois Lamarque, Andrew Conley, Warren G. Strand, and James B. White III

. Experiments analyzed here include twentieth-century simulations (1850–2005) with a combination of anthropogenic and natural forcings ( Gent et al. 2011 ), as well as experiments run with single forcings or a subset of combinations of forcings. The anthropogenic forcings in CCSM4 include time-evolving GHGs, as well as prescribed time- and space-evolving concentrations of tropospheric ozone, stratospheric ozone, the direct effect of sulfate aerosols (there are no indirect effects from sulfate or any other

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Dandan Zhao, Jinyuan Xin, Chongshui Gong, Xin Wang, Yongjing Ma, and Yining Ma

1. Introduction Aerosol is an important component of the atmosphere, and the study of aerosol has become a specific issue in basic and applied science ( Hansen et al. 2000 ; Haywood and Boucher 2000 ; IPCC 2001 ; Lee et al. 2007b ; Luo et al. 2000 ; Penner et al. 2001 ; Stocker et al. 2014 ). Large amounts of particulate matter can be inhaled by humans, resulting in health effects ( Fujii et al. 2001 ). Furthermore, the direct radiation effect of aerosols drives important changes in which

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Nathan P. Gillett, Vivek K. Arora, Damon Matthews, and Myles R. Allen

fluxes gives the derived cumulative emissions: anthropogenic emissions that when specified in a free CO 2 simulation would have given the same evolution of atmospheric CO 2 . We focus mainly on the 1PCT simulations here because TCRE is a metric of the response to CO 2 only and it is conventionally defined using such simulations ( Matthews et al. 2009 ). We also examine the response in simulations in which the CO 2 concentration is instantaneously quadrupled and then held constant (4×CO 2 ) for 10

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Zachary J. Lebo and Hugh Morrison

line was sensitive to the raindrop breakup parameterization implemented in a bulk microphysics model. Given that the ambient aerosol number concentration leads to substantial changes in droplet number and thus collection processes, it is postulated that increased anthropogenic aerosol loading could have similar effects on squall-line dynamics by impacting cold pool evolution. Since aerosols can affect cold pool characteristics because of their impact on cloud microphysics, RKW theory provides a

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Yonghui Lei, Brian Hoskins, and Julia Slingo

variations. However, the overall increase in rainfall intensity, which started in the late 1970s and peaked in the middle 1990s, may also contain discernible anthropogenic signals. Whether the slow downward trend in the early twenty-first century is due to natural decadal variations or the interplay of anthropogenic effects (global warming and aerosol loading) requires further research. The decrease of the light rainfall frequency may be mainly the result of anthropogenic climate changes. Associated with

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Gilbert P. Compo and Prashant D. Sardeshmukh

1. Introduction Distinguishing anthropogenic from natural climate variations is among the most important problems in climate research today. Three kinds of natural variations need to be considered. Variations of the first kind arise from changes in external radiative forcing associated with insolation changes and volcanic eruptions. Variations of the second kind are generated through internal dynamical mechanisms of coherent long-term variability in the ocean. Natural variations of the third

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Xiao-Ming Hu, Ming Xue, Petra M. Klein, Bradley G. Illston, and Sheng Chen

2000 ; Hu et al. 2013b ). Oke et al. (1991) used a simple energy balance model to assess the relative importance of the commonly stated intrinsic causes of UHI under calm and cloudless conditions, including anthropogenic heat, thermal properties/moisture availability of the materials of the city, street canyon geometry, and urban greenhouse gases. The first three of these were identified as the main intrinsic causative factors contributing to the UHII in a modeling study conducted by Ryu and

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