Journal of Geophysical Research: Atmospheres

Numerical analysis using WRF-SBM for the cloud microphysical structures in the C3VP field campaign: Impacts of supercooled droplets and resultant riming on snow microphysics

Authors

  • Takamichi Iguchi,

    Corresponding author
    1. Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA
    2. Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
      Corresponding author: T. Iguchi, Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA. (takamichi.iguchi@nasa.gov)
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  • Toshihisa Matsui,

    1. Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA
    2. Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
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  • Jainn J. Shi,

    1. Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
    2. Goddard Earth Sciences Technology and Research, Morgan State University, Baltimore, Maryland, USA
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  • Wei-Kuo Tao,

    1. Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
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  • Alexander P. Khain,

    1. Department of Atmospheric Sciences, Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
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  • Arthur Hou,

    1. Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
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  • Robert Cifelli,

    1. NOAA Earth System Research Laboratory, Boulder, Colorado, USA
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  • Andrew Heymsfield,

    1. National Center for Atmospheric Research, Boulder, Colorado, USA
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  • Ali Tokay

    1. Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
    2. Joint Center for Earth Systems Technology, University of Maryland, Baltimore, Maryland, USA
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Corresponding author: T. Iguchi, Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA. (takamichi.iguchi@nasa.gov)

Abstract

[1] Two distinct snowfall events are observed over the region near the Great Lakes during 19–23 January 2007 under the intensive measurement campaign of the Canadian CloudSat/CALIPSO validation project (C3VP). These events are numerically investigated using the Weather Research and Forecasting model coupled with a spectral bin microphysics (WRF-SBM) scheme that allows a smooth calculation of riming process by predicting the rimed mass fraction on snow aggregates. The fundamental structures of the observed two snowfall systems are distinctly characterized by a localized intense lake-effect snowstorm in one case and a widely distributed moderate snowfall by the synoptic-scale system in another case. Furthermore, the observed microphysical structures are distinguished by differences in bulk density of solid-phase particles, which are probably linked to the presence or absence of supercooled droplets. The WRF-SBM coupled with Goddard Satellite Data Simulator Unit (G-SDSU) has successfully simulated these distinctive structures in the three-dimensional weather prediction run with a horizontal resolution of 1 km. In particular, riming on snow aggregates by supercooled droplets is considered to be of importance in reproducing the specialized microphysical structures in the case studies. Additional sensitivity tests for the lake-effect snowstorm case are conducted utilizing different planetary boundary layer (PBL) models or the same SBM but without the riming process. The PBL process has a large impact on determining the cloud microphysical structure of the lake-effect snowstorm as well as the surface precipitation pattern, whereas the riming process has little influence on the surface precipitation because of the small height of the system.

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