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Eyal Ilotoviz, Alexander P. Khain, Nir Benmoshe, Vaughan T. J. Phillips, and Alexander V. Ryzhkov

particles such as graupel, hail, and FDs can contain unfrozen liquid at freezing temperatures. Freezing of the liquid is described by solving the corresponding heat balance equations at the particle surface and at the ice–liquid interfaces, according to Phillips et al. (2014 , 2015) . The balanced equations are written in the most general form that takes into account the thermodynamic effects of accretion of drops and ice crystals, as well as of shedding. At T < 0°C, the water mass within FDs

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Jiwen Fan, Yuan Wang, Daniel Rosenfeld, and Xiaohong Liu

1. Introduction Clouds regulate surface precipitation and the atmosphere’s radiative balance, therefore playing a significant role in the climate system. Clouds generally form when air is cooled and becomes supersaturated with respect to water or ice (except funnel clouds). The excess vapor generally cannot form cloud particles spontaneously owing to a high energy barrier, but rather condenses on aerosol particles that serve as either cloud condensation nuclei (CCN) or ice nuclei (IN

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Wojciech W. Grabowski and Hugh Morrison

role in the climate and climate change problem. The study reported here focuses on a very specific aspect: namely, the possible invigoration of deep convective clouds in polluted environments (e.g., Andreae et al. 2004 ; Rosenfeld et al. 2008 ). The invigoration has been argued to originate from the enhanced latent heating when large amounts of liquid water freeze after being transported above the 0°C level by convective updrafts, followed by off-loading of the frozen condensate through

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Wojciech W. Grabowski

from the enhanced latent heating when large amounts of liquid water freeze after being transported above the 0°C level by convective updrafts, followed by offloading of the frozen condensate through precipitation processes. The freezing alone is not sufficient to invigorate convective updrafts, as it merely balances the condensate loading associated with liquid water carried through the 0°C level. 1 The invigoration is argued to occur when collision–coalescence is suppressed in the lower portions

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

1. Introduction Aerosols contribute directly to atmospheric variability and to Earth’s radiative balance through scattering and absorption of solar radiation. Aerosols also contribute indirectly through complex aerosol–cloud interactions (ACI). The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) indicates that while the mechanisms of aerosol direct effects are well known, the uncertainties in the estimates of aerosol direct and indirect effects are larger than any

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Stacey Kawecki, Geoffrey M. Henebry, and Allison L. Steiner

water vapor and subsequently reduces drop sizes ( Twomey 1974 ). In mixed-phase clouds, aerosol effects are more complex because of multiple phase changes and the associated thermodynamic processes simultaneously occurring in different locations ( Seifert and Beheng 2006 ). The addition of CCN has competing effects on precipitation depending on whether warm or cold precipitation processes dominate; for example, warm precipitation processes will be suppressed, but cold precipitation processes can

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Tianmeng Chen, Jianping Guo, Zhanqing Li, Chuanfeng Zhao, Huan Liu, Maureen Cribb, Fu Wang, and Jing He

1. Introduction Aerosols can play an important role in Earth’s climate by altering the energy and water cycles ( Ramanathan et al. 2001 ; Rosenfeld et al. 2014 ). Various effects have been proposed that are now broadly referred to as the aerosol–radiation interactions (ARI) and aerosol–cloud–interactions (ACI) ( IPCC 2013 ). The mechanisms for ARI have been much better understood than ACI, even though very large uncertainties still exist in the former chiefly owing to a poor knowledge of the

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