On the impact of forced roll convection on vertical turbulent transport in cold air outbreaks

Research output: Contribution to journalArticleResearchpeer review

Authors

  • Micha Gryschka
  • Jens Fricke
  • Siegfried Raasch
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Details

Original languageEnglish
Pages (from-to)12,513-12,532
JournalJournal of Geophysical Research Atmospheres
Volume119
Issue number22
Early online date20 Nov 2014
Publication statusPublished - 27 Nov 2014

Abstract

We investigated the impact of roll convection on the convective boundary layer and vertical transports in different cold air outbreak (CAO) scenarios using large eddy simulations (LES). The organization of convection into rolls was triggered by upstream heterogeneities in the surface temperature, representing ice and water. By changing the sea ice distribution in our LES, we were able to simulate a roll and a nonroll case for each scenario. Furthermore, the roll wavelength was varied by changing the scale of the heterogeneity. The characteristics of the simulated rolls and cloud streets, such as aspect ratios, orientation of the roll axes, and downstream extensions of single rolls agreed closely with observations in CAO situations. The vertical turbulent fluxes, calculated for each simulation, were decomposed into contributions from rolls and from unorganized turbulence. Even though our results confirmed that rolls triggered by upstream heterogeneities can substantially contribute to vertical turbulent fluxes, the total fluxes were not affected by the rolls.

Keywords

    cold air outbreak, large eddy simulation, roll convection, turbulent fluxes

ASJC Scopus subject areas

Cite this

On the impact of forced roll convection on vertical turbulent transport in cold air outbreaks. / Gryschka, Micha; Fricke, Jens; Raasch, Siegfried.
In: Journal of Geophysical Research Atmospheres, Vol. 119, No. 22, 27.11.2014, p. 12,513-12,532.

Research output: Contribution to journalArticleResearchpeer review

Gryschka M, Fricke J, Raasch S. On the impact of forced roll convection on vertical turbulent transport in cold air outbreaks. Journal of Geophysical Research Atmospheres. 2014 Nov 27;119(22):12,513-12,532. Epub 2014 Nov 20. doi: 10.1002/2014JD022160
Gryschka, Micha ; Fricke, Jens ; Raasch, Siegfried. / On the impact of forced roll convection on vertical turbulent transport in cold air outbreaks. In: Journal of Geophysical Research Atmospheres. 2014 ; Vol. 119, No. 22. pp. 12,513-12,532.
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