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Title: Derivation of aerosol profiles for MC3E convection studies and use in simulations of the 20 May squall line case

Advancing understanding of deep convection microphysics via mesoscale modeling studies of well-observed case studies requires observation-based aerosol inputs. Here, we derive hygroscopic aerosol size distribution input profiles from ground-based and airborne measurements for six convection case studies observed during the Midlatitude Continental Convective Cloud Experiment (MC3E) over Oklahoma. We demonstrate use of an input profile in simulations of the only well-observed case study that produced extensive stratiform outflow on 20 May 2011. At well-sampled elevations between –11 and –23 °C over widespread stratiform rain, ice crystal number concentrations are consistently dominated by a single mode near ~400 µm in randomly oriented maximum dimension ( D max). The ice mass at –23 °C is primarily in a closely collocated mode, whereas a mass mode near D max ~1000 µm becomes dominant with decreasing elevation to the –11 °C level, consistent with possible aggregation during sedimentation. However, simulations with and without observation-based aerosol inputs systematically overpredict mass peak D max by a factor of 3–5 and underpredict ice number concentration by a factor of 4–10. Previously reported simulations with both two-moment and size-resolved microphysics have shown biases of a similar nature. Furthermore, the observed ice properties are notably similar to those reported from recentmore » tropical measurements. Based on several lines of evidence, we speculate that updraft microphysical pathways determining outflow properties in the 20 May case are similar to a tropical regime, likely associated with warm-temperature ice multiplication that is not well understood or well represented in models.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [5] ;  [6] ; ORCiD logo [6] ;  [7] ;  [7] ;  [8] ;  [8] ;  [9] ;  [9] ;  [10]
  1. NASA Goddard Institute for Space Studies, New York, NY (United States)
  2. Morgan State Univ., Baltimore, MD (United States); NASA Goddard Space Flight Center, Greenbelt, MD (United States)
  3. NASA Goddard Space Flight Center, Greenbelt, MD (United States); Science Systems and Applications, Inc., Lanham, MD (United States)
  4. NASA Goddard Institute for Space Studies, New York, NY (United States); Columbia Univ., New York, NY (United States)
  5. NASA Goddard Space Flight Center, Greenbelt, MD (United States)
  6. Univ. of Illinois, Urbana-Champaign, IL (United States)
  7. Univ. of Arizona, Tucson, AZ (United States)
  8. Univ. of Oklahoma and National Severe Storms Lab., Norman, OK (United States)
  9. Univ. of North Dakota, Grand Forks, ND (United States)
  10. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Report Number(s):
PNNL-SA-127242
Journal ID: ISSN 1680-7324; KP1704010
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 17; Journal Issue: 9; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1368108