Mistral and tramontane wind speed and wind direction patterns in regional climate simulations

  • The Mistral and Tramontane are important wind phenomena that occur over southern France and the northwestern Mediterranean Sea. Both winds travel through constricting valleys before flowing out towards the Mediterranean Sea. The Mistral and Tramontane are thus interesting phenomena, and represent an opportunity to study channeling effects, as well as the interactions between the atmosphere and land/ocean surfaces. This study investigates Mistral and Tramontane simulations using five regional climate models with grid spacing of about 50 km and smaller. All simulations are driven by ERA-Interim reanalysis data. Spatial patterns of surface wind, as well as wind development and error propagation along the wind tracks from inland France to offshore during Mistral and Tramontane events, are presented and discussed. To disentangle the results from large-scale error sources in Mistral and Tramontane simulations, only days with well simulated large-scale sea level pressure field patterns are evaluated. Comparisons with the observations show that the large-scale pressure patterns are well simulated by the considered models, but the orographic modifications to the wind systems are not well simulated by the coarse-grid simulations (with a grid spacing of about 50 km), and are reproduced slightly better by the higher resolution simulations. On days with Mistral and/or Tramontane events, most simulations underestimate (by 13 % on average) the wind speed over the Mediterranean Sea. This effect is strongest at the lateral borders of the main flow—the flow width is underestimated. All simulations of this study show a clockwise wind direction bias over the sea during Mistral and Tramontane events. Simulations with smaller grid spacing show smaller biases than their coarse-grid counterparts.

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Author:Anika Obermann, Sophie Bastin, Sophie Belamari, Dario Conte, Miguel Angel Gaertner, Laurent Li, Bodo AhrensORCiDGND
Parent Title (English):Climate dynamics
Place of publication:Berlin ; Heidelberg
Document Type:Article
Date of Publication (online):2016/11/28
Date of first Publication:2016/03/12
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2016/11/28
Tag:Bayesian network; Evaluation; Mistral; Model intercomparison; Regional climate models; Tramontane
Page Number:18
First Page:1
Last Page:18
© The Author(s) 2016. This article is published with open access at Springerlink.com. Open Access: This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Institutes:Geowissenschaften / Geographie / Geowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Open-Access-Publikationsfonds:Geowissenschaften / Geographie
Licence (German):License LogoCreative Commons - Namensnennung 4.0