Université de Fribourg

Evidence of response of vegetation to environmental change on high-elevation sites in the Swiss Alps

Keller, Franciska ; Kienast, F. ; Beniston, Martin

In: Regional Environmental Change, 2000, vol. 1(2), p. 70

Climate change has in the past led to shifts in vegetation patterns; in a future, warmer climate due to enhanced greenhouse-gas concentrations, vegetation is also likely to be highly responsive to such warming. Mountain regions are considered to be particularly sensitive to such changes. In this paper we present an approach to assess the impact of climate change on long-term vegetation plots...

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

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, no. 1-2, p. 19-31

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

Nonlinearities, feedbacks and critical thresholds within the earth's climate system

Rial, José A. ; Pielke, Roger A. ; Beniston, Martin ; Claussen, Martin ; Canadell, Josep ; Cox, Peter ; Held, Hermann ; Noblet-Ducoudré, Nathalie de ; Prinn, Ronald ; Reynolds, James F. ; Salas, José D.

In: Climatic Change, 2004, vol. 65, p. 11

The Earth's climate system is highly nonlinear: inputs and outputs are not proportional, change is often episodic and abrupt, rather than slow and gradual, and multiple equilibria are the norm. While this is widely accepted, there is a relatively poor understanding of the different types of nonlinearities, how they manifest under various conditions, and whether they reflect a climate system...

Université de Fribourg

Warm winter spells in the Swiss Alps: Strong heat waves in a cold season? A study focusing on climate observations at the Saentis high mountain site

Beniston, Martin

In: Geophysical Research Letters, 2005, vol. 32, p. L01812

Investigations conducted for several Swiss mountain climatological sites, and in particular the Saentis high mountain site at 2,500 m above sea level, show that positive temperature anomalies during the winter season currently exceed those of all other seasons. These “heat waves” exhibit daily maximum temperature anomalies sometimes in excess of 16°C, and are observed to have increased...