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Université de Fribourg

Numerical investigation of an extreme storm with the Canadian Regional Climate Model: the case study of windstorm VIVIAN, Switzerland, February 27, 1990

Goyette, Stéphane ; Beniston, Martin ; Caya, D. ; Laprise, R. ; Jungo, Patricia

In: Climate Dynamics, 2001, vol. 18(1-2), p. 145

The windstorm VIVIAN that severely affected Switzerland in February 1990 has been investigated using the Canadian Regional Climate Model (CRCM). This winter storm was characterised by a deep cyclone in the North Atlantic and by strong geopotential and baroclinic north-south gradients in the troposphere over Western Europe resulting in high windspeeds in Switzerland. Our principal emphasis is to...

Université de Fribourg

Daily wind gust speed probabilities over Switzerland according to three types of synoptic circulation

Jungo, Patricia ; Goyette, Stéphane ; Beniston, Martin

In: International Journal of Climatology, 2002, vol. 22(4), p. 485

The nowcasting and prediction of strong winds are still far from adequate, using either statistical or numerical modelling approaches. During the last decade, Switzerland has been struck by two extratropical storms, namely the February 1990 storm Vivian, and the December 1999 storm Lothar, that caused severe damage to infrastructure and to forests. Although numerical weather prediction models...

Université de Fribourg

Shifts in the distributions of pressure, temperature and moisture and changes in the typical weather patterns in the Alpine region in response to the behavior of the North Atlantic Oscillation

Beniston, Martin ; Jungo, Patricia

In: Theoretical and Applied Climatology, 2002, vol. 71(1-2), p. 29

An investigation has been undertaken to assess the manner in which the North Atlantic Oscillation (NAO) influences average, climatic conditions, and also extremes of dynamic and thermodynamic variables. By choosing representative sites in the Swiss Alps, the present study shows that there is a high sensitivity of the extremes of the probability density functions of temperature, moisture and...

Université de Fribourg

Climate modeling at various spatial and temporal scales: where can dendrochronology help ?

Beniston, Martin

In: Dendrochronologia, 2002, vol. 20 (1-2), p. 117

This paper provides a brief overview of certain issues related to climate modeling and the role that dendrochronology can play, and has already played, in this context. Modeling is an essential approach to investigating the future evolution of the climate system in response to human activities. Tree-ring chronologies, on the other hand, have the capability of providing key parameters for model...

Université de Fribourg

Climatic change: possible impacts on human health

Beniston, Martin

In: Swiss Medical Weekly, 2002, vol. 25-26, p. 329

This paper addresses a number of problems relating climatic change and human health. Following an introduction that outlines the over-arching issues, a short summary is given on climatic change and its anthropogenic causes. The rest of the paper then focuses on the direct and indirect impacts of global climatic change on health. Direct effects comprise changes in the hygrothermal stress response...

Université de Fribourg

Perturbations to astronomical observations at the European Southern Observatory's very large telescope site in Paranal, Chile: analyses of climatological causes

Beniston, Martin ; Casals, Paula ; Sarazin, Marc S.

In: Theoretical and Applied Climatology, 2002, vol. 73(3-4), p. 133-150

A study has been conducted to assess the reasons for a significant decrease in the astronomic observing period since the Very Large Telescope of ESO (the European Southern Observatory) went into operation in 1998. Following a multi-year monitoring of meteorological parameters at the site of the ESO telescope in Paranal (northern Chile), the optimal climatic conditions observed there prior to the...

Université de Fribourg

Snow pack in the Swiss Alps under changing climatic conditions: an empirical approach for climate impacts studies

Beniston, Martin ; Keller, Fransiska ; Goyette, Stéphane

In: Theoretical and Applied Climatology, 2003, vol. 74 (1-2), p. 19

In many instances, snow cover and duration are a major controlling factor on a range of environmental systems in mountain regions. When assessing the impacts of climatic change on mountain ecosystems and river basins whose origin lie in the Alps, one of the key controls on such systems will reside in changes in snow amount and duration. At present, regional climate models or statistical...

Université de Fribourg

Estimates of snow accumulation and volume in the Swiss Alps under changing climatic conditions

Beniston, Martin ; Keller, Fransiska ; Koffi, Brigitte ; Goyette, Stéphane

In: Theoretical and Applied Climatology, 2003, vol. 76, p. 125

Snow is a key feature of mountain environments in terms of the controls it exerts on hydrology, vegetation, and in terms of its economic significance (e.g., for the ski industry). Its quantification in a changing climate is thus important for various environmental and economic impact assessments. Based on observational analysis, surface energy balance modeling, and the latest data from...

Université de Fribourg

Climatic change in mountain regions: a review of possible impacts

Beniston, Martin

In: Climatic Change, 2003, vol. 59(1-2), p. 5

This paper addresses a number of issues related to current and future climatic change and its impacts on mountain environments and economies, focusing on the `Mountain Regions' Chapter 13 of Agenda 21, a basis document presented at the 1992 United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro, and the International Year of the Mountains (IYM) 2002. The awareness that...

Université de Fribourg

Application of a new wind gust parameterization: multiscale case studies performed with the Canadian regional climate model

Goyette, Stéphane ; Brasseur, Olivier ; Beniston, Martin

In: Journal of Geophysical Research, 2003, vol. 108(D13), no. 4374 doi:10.1029, p. 2002JD002646

The implementation of a physically based parameterization scheme for computation of wind gusts in a numerical regional climate model (RCM) is described in this paper. The method is based on an innovative approach proposed by Brasseur [2001] that assumes that gusts occurring at the surface result from the deflection of air parcels flowing higher in the boundary layer. Our parameterization scheme...