Journal of Geophysical Research: Atmospheres (1984–2012)

  1. Aerosol and Clouds

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    2. Aerosol and Clouds
    1. You have free access to this content
      Testing cloud microphysics parameterizations in NCAR CAM5 with ISDAC and M-PACE observations

      Xiaohong Liu, Shaocheng Xie, James Boyle, Stephen A. Klein, Xiangjun Shi, Zhien Wang, Wuyin Lin, Steven J. Ghan, Michael Earle, Peter S. K. Liu and Alla Zelenyuk

      Version of Record online: 24 DEC 2011 | DOI: 10.1029/2011JD015889

      Key Points

      • CAM5 underpredicts cloud liquid water content in Arctic low-level clouds
      • CAM5 underestimates surface downward longwave fluxes by 20-40 W m-2
      • Freezing temperature of rain has a substantial impact on modeled clouds
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      An examination of the aerosol semi-direct effect for a polluted case of the ISDAC field campaign

      J. D. Lindeman, Z. Boybeyi and I. Gultepe

      Version of Record online: 5 NOV 2011 | DOI: 10.1029/2011JD015649

      Key Points

      • Atmosphere is sensitive to changes in black carbon concentration
      • At Barrow, heating due to black carbon is localized in both altitude and time
      • A more stably stratified lower atmosphere reduces cloud amount
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      Factors influencing the microphysics and radiative properties of liquid-dominated Arctic clouds: Insight from observations of aerosol and clouds during ISDAC

      Michael E. Earle, Peter S. K. Liu, J. Walter Strapp, Alla Zelenyuk, Dan Imre, Greg M. McFarquhar, Nicole C. Shantz and W. Richard Leaitch

      Version of Record online: 4 NOV 2011 | DOI: 10.1029/2011JD015887

      Key Points

      • Aircraft observations of liquid-dominated Arctic stratocumulus clouds
      • Different cloud LWP and albedo, but similar droplet sizes, in clean and polluted conditions
      • Meteorological and microphysical factors involved, with possible second indirect effect
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      Toward ice formation closure in Arctic mixed-phase boundary layer clouds during ISDAC

      Alexander Avramov, Andrew S. Ackerman, Ann M. Fridlind, Bastiaan van Diedenhoven, Giovanni Botta, Kultegin Aydin, Johannes Verlinde, Alexei V. Korolev, J. Walter Strapp, Greg M. McFarquhar, Robert Jackson, Sarah D. Brooks, Andrew Glen and Mengistu Wolde

      Version of Record online: 13 OCT 2011 | DOI: 10.1029/2011JD015910

      Key Points

      • We found agreement between simulated and measured ice number concentrations
      • IN concentrations need to be sufficiently higher than ice concentrations
      • Properties of the observed ice crystals not well constrained by measurements
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      The influence of mixed-phase clouds on surface shortwave irradiance during the Arctic spring

      Dan Lubin and Andrew M. Vogelmann

      Version of Record online: 13 OCT 2011 | DOI: 10.1029/2011JD015761

      Key Points

      • ISDAC provided unique spectral irradiance measurements relevant to Arctic clouds
      • Mixed-phase attenuate more shortwave radiation than liquid water clouds
      • Nearly 75% of the observations show influence of mixed-phase cloud properties
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      Representation of Arctic mixed-phase clouds and the Wegener-Bergeron-Findeisen process in climate models: Perspectives from a cloud-resolving study

      Jiwen Fan, Steven Ghan, Mikhail Ovchinnikov, Xiaohong Liu, Philip J. Rasch and Alexei Korolev

      Version of Record online: 20 SEP 2011 | DOI: 10.1029/2010JD015375

      Key Points

      • Find that the WBF process only occurs in about 50% of the mixed-phase regime
      • Validate the w distribution and the liquid saturation used in GCMs
      • Suggestions for consistent subgrid treatments of cloud properties in GCMs
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      Effects of ice number concentration on dynamics of a shallow mixed-phase stratiform cloud

      Mikhail Ovchinnikov, Alexei Korolev and Jiwen Fan

      Version of Record online: 17 SEP 2011 | DOI: 10.1029/2011JD015888

      Key Points

      • Arctic mixed-phase stratus clouds are very sensitive to ice number concentration
      • Initial liquid water and radiative flux responses to ice number are linear
      • Early changes in cloud structure are from ice effects on buoyancy flux profile
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      Millimeter wave scattering from ice crystals and their aggregates: Comparing cloud model simulations with X- and Ka-band radar measurements

      Giovanni Botta, Kultegin Aydin, Johannes Verlinde, Alexander E. Avramov, Andrew S. Ackerman, Ann M. Fridlind, Greg M. McFarquhar and Mengistu Wolde

      Version of Record online: 15 SEP 2011 | DOI: 10.1029/2011JD015909

      Key Points

      • Importance of correct hydrometeor representation in electromagnetic models
      • Evaluation of new electromagnetic modeling technique for pristine and aggregates
      • Evaluation of CRM with radar observations
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      Representing the ice fall speed in climate models: Results from Tropical Composition, Cloud and Climate Coupling (TC4) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC)

      D. L. Mitchell, S. Mishra and R. P. Lawson

      Version of Record online: 14 SEP 2011 | DOI: 10.1029/2010JD015433

      Key Points

      • Improved estimates obtained for the ice fall velocity via recent field campaigns
      • The ice fall speed is well parameterized in terms of effective diameter
      • This links the climate feedback parameter to microphysics and radiation
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      Parameterizing correlations between hydrometeor species in mixed-phase Arctic clouds

      Vincent E. Larson, Brandon J. Nielsen, Jiwen Fan and Mikhail Ovchinnikov

      Version of Record online: 16 AUG 2011 | DOI: 10.1029/2010JD015570

      Key Points

      • We develop a method to parameterize correlations among hydrometeors
      • Our method is general and guarantees consistency among correlations
      • The correlations estimated by our method agree satisfactorily with LES