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

Ann M. Fridlind, Xiaowen Li, Di Wu, Marcus Van Lier-Walqui, Andrew S. Ackerman, Wei Kuo Tao, Greg M. McFarquhar, Wei Wu, Xiquan Dong, Jingyu Wang, Alexander Ryzhkov, Pengfei Zhang, Michael R. Poellot, Andrea Neumann, Jason M. Tomlinson

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15 Scopus citations

Abstract

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 (Dmax). The ice mass at-23 °C is primarily in a closely collocated mode, whereas a mass mode near Dmax ∼ 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 Dmax 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. The observed ice properties are notably similar to those reported from recent 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.

Original languageEnglish (US)
Pages (from-to)5947-5972
Number of pages26
JournalAtmospheric Chemistry and Physics
Volume17
Issue number9
DOIs
StatePublished - May 15 2017

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ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Fridlind, A. M., Li, X., Wu, D., Van Lier-Walqui, M., Ackerman, A. S., Tao, W. K., McFarquhar, G. M., Wu, W., Dong, X., Wang, J., Ryzhkov, A., Zhang, P., Poellot, M. R., Neumann, A., & Tomlinson, J. M. (2017). Derivation of aerosol profiles for MC3E convection studies and use in simulations of the 20 May squall line case. Atmospheric Chemistry and Physics, 17(9), 5947-5972. https://doi.org/10.5194/acp-17-5947-2017