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Shuyun Zhao, Hua Zhang, Zhili Wang, and Xianwen Jing

drivers of climate change that are significantly influenced by human activities. The overall radiative forcing of anthropogenic aerosols is negative and can offset a large portion of the global warming caused by greenhouse gases. The effects of anthropogenic aerosols on regional climate, especially over monsoon regions, have been investigated in many studies. For example, it was found that anthropogenic aerosols could weaken the East Asian summer monsoon ( Zhang et al. 2012 ) and the South Asian

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Shao-Yi Lee, Ho-Jeong Shin, and Chien Wang

1. Introduction Field observations in recent decades have revealed an abundance of anthropogenic aerosols, particularly absorbing aerosols, over South Asia and its surrounding ocean during the dry season ( Ramanathan et al. 2001 ). Modeling studies and observation-based analyses have indicated that the radiative effects of these aerosols can interrupt not just localized meteorological features but also large-scale climate features such as monsoons. Using prescribed direct radiative forcing

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Jiechun Deng, Aiguo Dai, and Haiming Xu

.1016/j.atmosenv.2012.12.039 . 10.1016/j.atmosenv.2012.12.039 Jiang , Y. , X. Q. Yang , and X. Liu , 2015 : Seasonality in anthropogenic aerosol effects on East Asian climate simulated with CAM5 . J. Geophys. Res. , 120 , 10 837 – 10 861 , . 10.1002/2015JD023451 Kjellsson , J. , 2015 : Weakening of the global atmospheric circulation with global warming . Climate Dyn. , 45 , 975 – 988 , . 10.1007/s00382

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Marco Marani

potential anthropogenic effects (e.g., due to nearby industrial or urban areas). 2. The chi-square and the balls-in-boxes tests Here, a “wet day” is defined as any day, say, the i th day in the sequence, for which the daily rainfall amount h i ≥ h t , where h t is a selected threshold. We wish to test against the null hypothesis that wet days arrive on any day of the week with equal probability . Let n k indicate the number of wet days occurring on the k th day of the week and n = ∑ 1 7 n

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Kirsten L. Findell, Elena Shevliakova, P. C. D. Milly, and Ronald J. Stouffer

since humans first began to modify the face of the land through agriculture and other activities; we are comparing a potential vegetation state (no human disturbance) to the present-day condition. Not all impacts resulting from these changes would be captured by a time series of the most recent 130 years. These two factors suggest that our experiments place an upper bound on the potential impact of the biophysical effects of anthropogenic land cover change. Thus, if land cover change was the major

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Yuan Sun, Zhong Zhong, Tim Li, Lan Yi, and Yixuan Shen

stronger (weaker) TCs tend to be controlled more by upper-level (lower-level) steering flow. Our results further indicate that the changes of TC tracks (including interbasin trend and latitudinal shift) make a much larger contribution to the slowing trend compared with the weakening of tropical circulation, which is related to anthropogenic warming. Note that the effects of interbasin trend and latitudinal shift are not independent of each other; they are largely coincident with each other, and hard to

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Rei Chemke and Guy Dagan

and Sherwood 2011 ). The latter is driven by the direct effect of anthropogenic aerosols. In this study, an idealized GCM is used to study the effects of the spatial distribution of the direct anthropogenic ARF on the general circulation. While most previous studies investigated the effects of the global ARF on the general circulation (mostly in the tropics), here, by spatially decomposing the ARF, we study the dynamical and thermodynamical responses of the atmosphere to different spatial

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Duo Chan and Qigang Wu

1. Introduction Attribution studies have indicated that it is extremely likely that there has been a substantial anthropogenic contribution to global and continental surface air temperature (SAT) increases since the middle of the twentieth century ( Hegerl et al. 2007 ; Bindoff et al. 2014 ). On subcontinental and smaller scales, the relative contribution of internal variability compared to the forced response to observed changes tends to be larger, since spatial differences in internal

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S. J. Ghan, X. Liu, R. C. Easter, R. Zaveri, P. J. Rasch, J.-H. Yoon, and B. Eaton

1. Introduction Anthropogenic aerosol is thought to play an important role in driving climate change, but its role is so complex that uncertainty in estimates of radiative forcing of climate change is dominated by uncertainty associated with forcing by anthropogenic aerosol ( Forster et al. 2007 ). This complexity arises because anthropogenic aerosol alters the planetary energy balance through a variety of mechanisms operating across a wide range of spatial scales: direct effects ( Haywood and

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Shao-Yi Lee and Chien Wang

subcontinent. High amounts of precipitation occur in this season, particularly over southwestern India as well as northeastern India where the monsoon flow meets orography. In the past decade, there has been an increase in studies on the effects of anthropogenic aerosols on the South Asian summer monsoon because of concerns over the climate effects of the escalating abundance of anthropogenic aerosols over South Asia and surrounding regions. The persistent aerosol layer in the region, or the “atmospheric

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