Université de Fribourg

Spatio-temporal variations of rockfall activity into forests results from tree-ring and tree analysis

Stoffel, Markus ; Monbaron, Michel (Dir.) ; Kienholz, Hans (Codir.) ; Strunk, Horst (Codir.) ; Raetzo, Hugo (Codir.)

Thèse de doctorat : Université de Fribourg, 2005 ; Nr. 1480.

Rockfall represents one of the most common geomorphological processes in mountain regions and has extensively been studied in the past. Nonetheless, detailed data on frequencies (how often), volumes (how large), spatial distributions (where) or the seasonality (when) of rockfall activity remain scarce and most of the time fragmentary. Similarly, tree-ring analysis has only exceptionally been used...

Université de Fribourg

Relationship between hailfall intensity and hail damage on ground, determined by radar and lightning observations

Hohl, Roman Marco ; Beniston, Martin (Dir.)

Thèse de doctorat : Université de Fribourg, 2001 ; no 1357.

Weather radars are now available in many countries for operational observations and measurements of hailstorms and provide detailed information on the formation and structure of severe thunderstorms. Much research has been devoted to the quantitative measurement of hailfalls and the nowcasting of hail-bearing thunderstorms which is of interest for national weather services and airports (warning),...

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...