Idealized Simulations of a Squall Line from the MC3E Field Campaign Applying Three Bin Microphysics Schemes: Dynamic and Thermodynamic Structure

Journal Article · Thu Nov 30 23:00:00 EST 2017 · Monthly Weather Review

DOI:https://doi.org/10.1175/MWR-D-16-0385.1· OSTI ID:1410593

Xue, Lulin ^[1]; Fan, Jiwen ^[2]; Lebo, Zachary J. ^[3]; Wu, Wei ^[4]; Morrison, Hugh ^[1]; Grabowski, Wojciech W. ^[1]; Chu, Xia ^[3]; Geresdi, István ^[5]; North, Kirk ^[6]; Stenz, Ronald ^[7]; Gao, Yang ^[2]; Lou, Xiaofeng ^[8]; Bansemer, Aaron ^[1]; Heymsfield, Andrew J. ^[1]; McFarquhar, Greg M. ^[4]; Rasmussen, Roy M. ^[1]

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1. National Center for Atmospheric Research, Boulder, Colorado
2. Pacific Northwest National Laboratory, Richland, Washington
3. University of Wyoming, Laramie, Wyoming
4. National Center for Atmospheric Research, Boulder, Colorado, University of Illinois at Urbana–Champaign, Urbana, Illinois
5. University of Pécs, Pécs, Hungary
6. McGill University, Montréal, Québec, Canada
7. University of North Dakota, Grand Forks, North Dakota
8. Chinese Academy of Meteorological Sciences, Beijing, China

The squall-line event on 20 May 2011, during the Midlatitude Continental Convective Clouds (MC3E) field campaign has been simulated by three bin (spectral) microphysics schemes coupled into the Weather Research and Forecasting (WRF) Model. Semi-idealized three-dimensional simulations driven by temperature and moisture profiles acquired by a radiosonde released in the preconvection environment at 1200 UTC in Morris, Oklahoma, show that each scheme produced a squall line with features broadly consistent with the observed storm characteristics. However, substantial differences in the details of the simulated dynamic and thermodynamic structure are evident. These differences are attributed to different algorithms and numerical representations of microphysical processes, assumptions of the hydrometeor processes and properties, especially ice particle mass, density, and terminal velocity relationships with size, and the resulting interactions between the microphysics, cold pool, and dynamics. This study shows that different bin microphysics schemes, designed to be conceptually more realistic and thus arguably more accurate than bulk microphysics schemes, still simulate a wide spread of microphysical, thermodynamic, and dynamic characteristics of a squall line, qualitatively similar to the spread of squall-line characteristics using various bulk schemes. Future work may focus on improving the representation of ice particle properties in bin schemes to reduce this uncertainty and using the similar assumptions for all schemes to isolate the impact of physics from numerics.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0008648; SC0014065; SC0016476; AC06-76RL01830
• OSTI ID: 1410593
• Alternate ID(s): OSTI ID: 1430449; OSTI ID: 1594795
• Journal Information: Monthly Weather Review, Journal Name: Monthly Weather Review Journal Issue: 12 Vol. 145; ISSN 0027-0644
• Publisher: American Meteorological Society
• Country of Publication: United States
• Language: English