Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
doi:10.5194/acp-2016-900
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
24 Oct 2016
Review status
A revision of this discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Large-eddy simulation of radiation fog: Part 1: Impact of dynamics on microphysics
Marie Mazoyer1, Christine Lac1, Odile Thouron2, Thierry Bergot1, Valery Masson1, and Luc Musson-Genon3 1CNRM (CNRS-Meteo-France), UMR3589, Toulouse, France
2CERFACS, Toulouse, France
3CEREA, France
Abstract. Large Eddy Simulations (LES) of a radiation fog event occurring during ParisFog experiment have been studied with a view of analyzing the impact of the dynamics on the microphysics. The LES, performed with the Meso-NH model at 5 m resolution horizontally and 1 m vertically, and with a 2-moment microphysical scheme, included the drag effect of a trees barrier and deposition on vegetation. The model shows a good agreement with the measurements of the near surface dynamic and thermodynamic parameters as well as the cloud water content, but overestimates the cloud droplet sizes and concentration. The blocking effect of the trees induced elevated fog formation, like in the observation, and horizontal heterogeneities, and limited the cooling and the cloud water production. The deposition process was found to exert the most significant impact on the fog prediction, as it not only erodes the fog near the surface, but also modifies the fog life cycle and induces vertical heterogeneities. The comparison with the 2 m horizontal resolution simulation exhibited small differences meaning that the grid convergence was achieved. Conversely, increasing numerical diffusion through a wind advection operator of lower order led to an overestimation of the near surface microphysical fields and had almost a similar effect than removing the effect of the trees barrier. This study allows to establish the major dynamical ingredients necessary to perform correctly the fog life cycle prediction at high resolution.

Citation: Mazoyer, M., Lac, C., Thouron, O., Bergot, T., Masson, V., and Musson-Genon, L.: Large-eddy simulation of radiation fog: Part 1: Impact of dynamics on microphysics, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-900, in review, 2016.
Marie Mazoyer et al.
Marie Mazoyer et al.
Marie Mazoyer et al.

Viewed

Total article views: 379 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
277 78 24 379 14 28

Views and downloads (calculated since 24 Oct 2016)

Cumulative views and downloads (calculated since 24 Oct 2016)

Viewed (geographical distribution)

Total article views: 379 (including HTML, PDF, and XML)

Thereof 377 with geography defined and 2 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 26 May 2017
Publications Copernicus
Download
Short summary
Large Eddy Simulations of a radiation fog event occurring during ParisFog experiment have been studied to analyze the impact of the dynamics on the microphysics. They included a sophisticated microphysical scheme, the drag effect of a trees barrier and deposition on vegetation. They showed a good agreement with the measurements but overestimated the cloud droplet concentration. The deposition process was found to exert the most significant impact on the fog prediction.
Large Eddy Simulations of a radiation fog event occurring during ParisFog experiment have been...
Share