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Jianjun Liu, Zhanqing Li, and Maureen Cribb

decreased from the surface to high altitudes and that most aerosol particles were located in the boundary layer over the North Atlantic region. Under more stable atmospheric conditions, CBHs are generally lower than those under less stable conditions (e.g., Fig. 5a ) and thus can mix and interact more with aerosols, resulting in a larger FIE ( Jones et al. 2009 ; Costantino and Bréon 2013 ). This is confirmed by the relationship between DER and under constant LWP conditions for samples with low and

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Peter J. Marinescu, Susan C. van den Heever, Max Heikenfeld, Andrew I. Barrett, Christian Barthlott, Corinna Hoose, Jiwen Fan, Ann M. Fridlind, Toshi Matsui, Annette K. Miltenberger, Philip Stier, Benoit Vie, Bethan A. White, and Yuwei Zhang

in the boundary layer and free troposphere from aircraft during the Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaign, which had operations near Houston, in September 2013 ( NASA LARC 2014 ; Sawamura et al. 2017 ) . In addition to the aerosol number concentration profiles, uniform aerosol number size distributions were also specified using a lognormal distribution with a geometric mean diameter of 100

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Wojciech W. Grabowski

regime change; this does not apply to the case considered here.) The forcings refer to a prescribed initial meteorological situation (e.g., the sounding), surface sensible and latent heat fluxes, radiative cooling of the atmosphere, and the large-scale advection of temperature and moisture. The latter can be included through realistic lateral boundary conditions [as in typical limited-area numerical weather prediction (NWP) simulations] or through prescribed tendencies imposed over a finite

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

). For lateral meteorological boundary conditions, we use NAM-Reanalysis 12-km data ( NCEI 2013 ; http://nomads.ncdc.noaa.gov/data.php ) every six hours. Although a resolution of 250 m may be required to resolve the convective updrafts ( Bryan et al. 2003 ), a 4-km grid size has been shown to be sufficient for resolving the potential for severe weather ( Weisman et al. 1997 ), and we do not incorporate a cumulus scheme based on this horizontal resolution. Table 1 describes the full suite of

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Yvonne Boose, Zamin A. Kanji, Monika Kohn, Berko Sierau, Assaf Zipori, Ian Crawford, Gary Lloyd, Nicolas Bukowiecki, Erik Herrmann, Piotr Kupiszewski, Martin Steinbacher, and Ulrike Lohmann

observations by Knopf et al. (2014) for a boundary layer site. e. In and out of clouds, wind direction, and other meteorological parameters During CLACE2014, 68% of the INP measurements were made during in-cloud conditions. Table 4 summarizes the median aerosol particle and INP concentrations in and out of cloud. There were, on average, a factor of 2 more aerosol particles in the size range of the CPC (≥0.01 μ m) during cloud-free periods than during cloudy ones. Yet a larger (20%) total aerosol

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Yun Lin, Yuan Wang, Bowen Pan, Jiaxi Hu, Yangang Liu, and Renyi Zhang

dominated by the inorganic fraction ( Guo et al. 2014 ). Nucleation scavenging is the only mechanism to remove aerosols in our scheme, and aerosol regeneration from droplet evaporation is not considered. Under favorable wind conditions, aerosols with a fixed number and mass concentration at the lateral boundaries of the outer domain are transported through advection and convection to provide an additional aerosol source for the inner domain. The heterogeneous ice nucleation and homogeneous freezing

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

conditions such as temperature and stability, cloud formation, convection, and even large-scale circulation (e.g., Lau et al. 2006 ; Bollasina et al. 2011 ; Nabat et al. 2015 ; Y. Wang et al. 2014c ; Sanap and Pandithurai 2015 ; Fan et al. 2015a ). Scattering aerosols generally cool the surface in clear-sky conditions. For strongly absorbing aerosol particles like black carbon ( Peng et al. 2016b ), they also heat some part of atmosphere depending on the locations (horizontally and vertically

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Yan Yang, Jiwen Fan, L. Ruby Leung, Chun Zhao, Zhanqing Li, and Daniel Rosenfeld

/aerosol conditions in all simulated cases. The simulation is performed at 3 × 3 km 2 horizontal resolution with 420 × 420 grid cells (31°–39°N, 104°–115°E) and 40 vertical layers up to 50 hPa. The model domain covers a large part of central China ( Fig. 1a ) and is centered at Guanzhong Plain as shown in Fig. 1b . The meteorological initial and lateral boundary conditions are derived from the National Centers for Environmental Prediction Final Analysis (NCEP FNL) data at 1° horizontal resolution and 6-h

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Baolin Jiang, Bo Huang, Wenshi Lin, and Suishan Xu

present, second- to sixth-order advection schemes are available for both vertical and horizontal directions. The available lateral boundary conditions include periodic, open symmetric, and specified options, while the bottom boundary conditions contain physical and free-slip options. Currently, cloud microphysics, cumulus parameterization, surface physics, planetary boundary layer physics, and atmospheric radiation physics are included in the model physics component. A variety of coupled physical and

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

can be measured under all sky conditions and at most weather stations. In comparison, aerosol optical depth (AOD), a more quantitative measure of aerosol loading in terms of light attenuation, can only be retrieved under cloud-free conditions such as those from the spaceborne passive remote sensors [e.g., the Moderate Resolution Imaging Spectroradiometer (MODIS)]. Note that for ACI studies, it is the CCN that are most relevant but its measurements are more scarce, and there exist large

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