The Impact of Diurnal Cycle on a Low-Froude Number Flow Observed during the PYREX Experiment

Marc Georgelin Laboratoire d'Aérologie, UMR CNRS/Université Paul Sabatier, Toulouse, France

Search for other papers by Marc Georgelin in
Current site
Google Scholar
PubMed
Close
,
Evelyne Richard Laboratoire d'Aérologie, UMR CNRS/Université Paul Sabatier, Toulouse, France

Search for other papers by Evelyne Richard in
Current site
Google Scholar
PubMed
Close
, and
Monique Petididier Centre d'étude des Environnements Terrestre et Planétaires, UPR CNRS, Saint Maur, France

Search for other papers by Monique Petididier in
Current site
Google Scholar
PubMed
Close
Restricted access

We are aware of a technical issue preventing figures and tables from showing in some newly published articles in the full-text HTML view.
While we are resolving the problem, please use the online PDF version of these articles to view figures and tables.

Abstract

The intensive observing period (IOP) 4 of the Pyrenees Experiment (PYREX) has been simulated with a hydrostatic three-dimensional model. The PYREX IOP 4 was devoted to the observation of the orographically generated flow above and around the Pyrenees Mountains located at the French–Spanish border. Two simulations, with or without surface thermal forcing, have been performed. Their results are described and compared with the PYREX observations. The influence of thermal forcing is assessed on the main characteristics of the flow, including the upwind flow reversal, the vertically propagating mountain wave, the regional winds created by the flow deviation around the mountain, and the lee vortices. Prominent alterations of the flow are found downwind of the mountain where the diurnal cooling induces the disappearance of the lee vortices and the heating significantly reduces the intensity of the low-level deviated flow.

Abstract

The intensive observing period (IOP) 4 of the Pyrenees Experiment (PYREX) has been simulated with a hydrostatic three-dimensional model. The PYREX IOP 4 was devoted to the observation of the orographically generated flow above and around the Pyrenees Mountains located at the French–Spanish border. Two simulations, with or without surface thermal forcing, have been performed. Their results are described and compared with the PYREX observations. The influence of thermal forcing is assessed on the main characteristics of the flow, including the upwind flow reversal, the vertically propagating mountain wave, the regional winds created by the flow deviation around the mountain, and the lee vortices. Prominent alterations of the flow are found downwind of the mountain where the diurnal cooling induces the disappearance of the lee vortices and the heating significantly reduces the intensity of the low-level deviated flow.

Save