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Rebetez, Martine

Nom
Rebetez, Martine
Affiliation principale
Site web
Fonction
Professeure ordinaire
Email
martine.rebetez@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/403

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  • Publication
    Métadonnées seulement
    Heat and drought 2003 in Europe: a climate synthesis
    (2006)
    Rebetez, Martine 
    ;
    Mayer, Helmut
    ;
    Dupont, Olivier
    ;
    Schindler, Dirk
    ;
    Gartner, Karl
    ;
    Kropp, Jürgen
    ;
    Menzel, Anette
    Heat and drought were extreme in summer 2003 in Europe. Climatic data show that most extreme were maximum air temperatures in June and August; maps of these two months show a striking similarity in geographical range. Over wide regions, monthly mean temperatures were more than 4 degrees C above the long term mean values. The heat lasted from May to September in large parts of western and central Europe. The lack of precipitation was most severe in summer 2003 but precipitation was generally below normal from February 2003 until June 2004 ( with the exception of two months). Sunshine duration was above normal, particularly in regions which usually have rainy and cloudy episodes in summer, and relative air humidity was below normal during the whole year of 2003. The drought experienced by the vegetation in summer 2003 was exacerbated by the length of the period with scarce precipitation and humidity, by the heat during the summer and by long sunshine duration.
  • Publication
    Métadonnées seulement
    To what extent can oxygen isotopes in tree rings and precipitation be used to reconstruct past atmospheric temperature? A case study
    (2003)
    Rebetez, Martine 
    ;
    Saurer, Matthias
    ;
    Cherubini, Paolo
    We analyzed the relationship between air temperature and oxygen isotopes measured in tree rings of silver fir (Abies alba Mill.) from a long-term forest ecosystem research plot in the Swiss Jura mountains (LWF project). The oxygen isotope data were compared with a century-long meteorological series of air temperature data. Measurements of oxygen isotope ratios in precipitation were also used for comparison. Results show that the late-wood tree-ring series is significantly correlated with May to August temperatures. Correlations were higher for maximum (daytime) air temperature and even better for air temperature measured on rainy days only. We stress that trends in maximum temperature series for this time of the year, like trends in oxygen isotope ratios series from tree rings, are completely different from trends in yearly mean temperature. Indeed, maximum temperature trends during the vegetation period slightly decreased during the 20th century, whereas yearly means increased strongly.
  • Publication
    Accès libre
    Changes in daily and nightly day-to-day temperature variability during the twentieth century for two stations in Switzerland
    (2001)
    Rebetez, Martine 
    An analysis of day-to-day variability was performed on two century-longs daily minimum and maximum temperature series from Switzerland. Warmer temperatures during the 20(th) century have been accompanied by a reduction in day-to-day variability, particularly for minimum temperatures and for winter. There is a significant negative correlation between day-to-day variability and the skewness of the temperature distribution, particularly in winter and for minimum temperatures. Lower variability is linked to a reduced number of cold days and nights. Higher NAO index values tend to be associated not only with warmer temperatures but also with lower day-to-day variability. This paper confirms that the temperature warming during the 20(th) century has happened mainly through the loss of the coldest part of the series, not only in the 24-hour or yearly cycle, but also through the loss of the coldest episodes in each month.
  • Publication
    Accès libre
    Progress in the study of climatic extremes in northern and central Europe
    (1999)
    Heino, R
    ;
    Brazdil, R
    ;
    Forland, E
    ;
    Tuomenvirta, H
    ;
    Alexandersson, H
    ;
    Beniston, Martin
    ;
    Pfister, Christian
    ;
    Rebetez, Martine 
    ;
    Rosenhagen, G
    ;
    Rosner, S
    ;
    Wibig, J
    A study of the long-term changes of various climatic extremes was made jointly by a number of European countries. It was found that the changes in maximum and minimum temperatures follow, in broad terms, the corresponding well-documented mean temperature changes. Minimum temperatures, however, have increased slightly more than maximum temperatures, although both have increased. As a result, the study confirms that the diurnal temperature range has mostly decreased during the present century in Northern and Central Europe. Frost has become less frequent. Two extreme-related precipitation characteristics, the annual maximum daily precipitation and the number of days with precipitation greater than or equal to 10 mm, show no major trends or changes in their interannual variability. An analysis of return periods indicated that in the Nordic countries there were high frequencies of 'extraordinary' 1-day rainfalls both in the 1930s and since the 1980s. There have been no long-term changes in the number of high wind speeds in the German Eight. Occurrences of thunderstorms and hails show a decreasing tendency in the Czech Republic during the last 50 years. Finally, using proxy data sources, a 500-year temperature and precipitation event graph for the Swiss Mittelland is presented. It shows large interdecadal variations as well as the exceptionality of the latest decade 1986-1995.
  • Publication
    Accès libre
    Changes in sunshine duration are correlated with changes in daily temperature range this century: An analysis of Swiss climatological data
    (1998)
    Rebetez, Martine 
    ;
    Beniston, Martin
    Analyses of the relationship between trends in daily temperature range and those of sunshine duration in the Swiss Alps show a strong correlation at lower elevation sites. The decrease in daily temperature range is associated with a corresponding decrease in sunshine duration. At high elevations, however, this relationship is absent. The decrease in daily temperature range observed this century at lower elevation sites is inferred to be a consequence of an increase in low-level cloudiness. Higher elevation sites lie above the low-level cloud layers and the moisture-laden lower atmospheric boundary layer and as a result do not exhibit the same trends.