Cloud-Resolving Model Intercomparison of an MC3E Squall Line Case: Part II. Stratiform Precipitation Properties

Journal Article · Tue Jan 22 00:00:00 EST 2019 · Journal of Geophysical Research: Atmospheres

DOI:https://doi.org/10.1029/2018JD029596· OSTI ID:1507531

Han, Bin  ^[1]; Fan, Jiwen  ^[2]; Varble, Adam  ^[3]; Morrison, Hugh  ^[4]; Williams, Christopher R.  ^[5]; Chen, Baojun  ^[6]; Dong, Xiquan  ^[7]; Giangrande, Scott E.  ^[8]; Khain, Alexander  ^[9]; Mansell, Edward  ^[10]; Milbrandt, Jason A. ^[11]; Shpund, Jacob ^[9]; Thompson, Gregory  ^[4]

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1. School of Atmospheric SciencesNanjing University Nanjing China; Pacific Northwest National Laboratory Richland WA USA
2. Pacific Northwest National Laboratory Richland WA USA
3. Pacific Northwest National Laboratory Richland WA USA; Department of Atmospheric SciencesUniversity of Utah Salt Lake City UT USA
4. National Center for Atmospheric Research Boulder CO USA
5. Cooperative Institute for Research in Environmental SciencesUniversity of Colorado Boulder and NOAA/Earth System Research Laboratory Boulder CO USA
6. School of Atmospheric SciencesNanjing University Nanjing China
7. Department of Hydrology and Atmospheric SciencesUniversity of Arizona Tucson Arizona USA
8. Environmental and Climate Sciences DepartmentBrookhaven National Laboratory Upton NY USA
9. The Institute of the Earth ScienceThe Hebrew University of Jerusalem Jerusalem Israel
10. NOAA/OAR/National Severe Storms Laboratory Norman OK USA
11. Meteorological Research DivisionEnvironment and Climate Change Canada Dorval Canada

In this second part of a cloud microphysics scheme intercomparison study, we focus on biases and variabilities of stratiform precipitation properties for a mid-latitude squall line event simulated with a cloud-resolving model implemented with eight cloud microphysics schemes. Most of the microphysics schemes underestimate total stratiform precipitation, mainly due to underestimation of stratiform precipitation area. All schemes underestimate the frequency of moderate stratiform rain rates (2-6 mm h-1), which may result from low-biased ice number and mass concentrations for 0.2-2 mm diameter particles in the stratiform ice region. Most simulations overestimate ice water content (IWC) at altitudes above 7 km for temperatures colder than -20°C but produce a decrease of IWC approaching the melting level, which is opposite to the trend shown by in-situ observations. This leads to general underestimations of stratiform IWC below 5-km altitude and rain water content above 1-km altitude for a given rain rate. Stratiform precipitation area (SPA) positively correlates with the convective condensate detrainment flux but is modulated by hydrometeor type, size, and fall speed. SPA also changes by up to 17-25% through alterations of the lateral boundary condition forcing frequency. Stratiform precipitation, rain rate, and area across the simulations varies by a factor of 1.5. This large variability is primarily a result of variability in the downward stratiform ice mass flux, which is highly correlated with convective condensate horizontal detrainment strength. The variability of simulated local microphysical processes in the stratiform region plays a secondary role in explaining variability in simulated stratiform rainfall properties.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1507531
• Report Number(s): PNNL-SA-140585
• Journal Information: Journal of Geophysical Research: Atmospheres, Vol. 124, Issue 2; ISSN 2169-897X
• Publisher: American Geophysical Union
• Country of Publication: United States
• Language: English