An analysis of regional climate change in Switzerland
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An analysis of daily climatological data covering the period from 1901 to 1992 for four locations in Switzerland (Zurich, Lugano, Davos, and Säntis) has been made. The study has highlighted the fact that climate change this century is characterized by increases in minimum temperatures of about 2 K, a more modest increase in maximum temperatures (in some instances a decrease of maxima in the latter part of the record), little trend in the precipitation data, and a general decrease of sunshine duration through to the mid 1980s. The interannual variability is generally large, and filtering of the data to remove high-frequency noise shows that the regional climate undergoes a series of fluctuations of between 8 and 20 years' duration. The temperature change over this century is of greater magnitude than the global temperature changes published in the literature, reflecting an amplification of the global signal in the Alpine region; warming has been most intense in the 1940s, followed by the 1980s; the cooling which intervened from the 1950s to the late 1970s was not sufficient to offset the warming in the middle of the century.
Pressure statistics have been compiled as a means of providing a link between the regional-scale climatological variables and the synoptic, supra-regional scale. These statistics show that pressure also exhibits a number of decadal-scale fluctuations, with the appearance of a new and anomalous behavior in the 1980s; in this decade, pressure reaches annual average values far higher than at other times this century. The pressure field is well correlated with the North Atlantic Oscillation (NAO) Index for distinct periods of the record (1931–1950 and 1971–1990) and is almost decorrelated from the NAO Index for the other decades of the century; this is indicative of transition from one climatic régime to another, dominated by zonal flow when the correlation with the NAO Index is high. In the 1980s, when zonal flow over the North Atlantic is strong, episodes of persistent, anomalously high pressures (blocking highs) are seen to occur over Switzerland, particularly during the winter season. The difference between the zonal and non-zonal régimes is particularly marked between the decade of the 1950s and that of the 1980s.
The impact of this change between the 1950s and the 1980s on a number of climatological variables has been investigated statistically in order to provide an illustration of the manner in which changes in synoptic régimes (i.e., ‘climate change’) impacts upon climate characteristics on a regional scale. The analysis shows that temperature, precipitation, snow depth, and sunshine duration are indeed sensitive to large-scale influences; not only can yearly mean changes be quantified, but also seasonal and monthly fluctuations.
KeywordsClimate Change Regional Climate Interannual Variability Snow Depth North Atlantic Oscillation
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- Balling, R. C., 1992:The Heated Debate: Greenhouse Predictions Versus Climate Reality. San Francisco: Pacific Research Institute Press, 195 pp.Google Scholar
- Bantle, H., 1989: Programmdokumentation Klima-Datenbank am RZ-ETH Zürich, Swiss Meteorological Insititute, Zürich.Google Scholar
- Beniston, M. (ed.), 1994:Mountain Environments in Changing Climates. London: Routledge (in press, approx. 550 pp).Google Scholar
- Boden, T. A., Kanciruk, P., Farrell, M. P., 1990: Trends '90: A compendium of data on global change. Oak Ridge, Tennessee: Carbon Dioxide Information Analysis Center, Environmental Sciences Division, Oak Ridge National Laboratory, USA.Google Scholar
- Diaz, H. F., Markgraf, V. (eds.), 1992:El Niño, Historical and Paleoclimatic Aspects of the Southern Oscillation. Cambridge, UK: Cambridge University Press, 476 pp.Google Scholar
- Diaz, H. F., Bradley, R. S., Eischeid, J. K., 1989: Precipitation fluctuations over global land areas since the late 1800s.J. Geophys. Res. 94, 1195–1210.Google Scholar
- Hansen, A. R., Pandolfo, J. P., Sutera, A., 1993: Midtropospheric flow regimes and persistent wintertime anomalies of surface-layer pressure and temperature.J. Climatol. 6, 2136–2143.Google Scholar
- Houghton, J. T., Jenkins, G. J., Ephraums, J. J. (eds.), 1990:Climate Change — The IPCC Scientific Assessment. Cambridge: Cambridge University Press, 365 pp.Google Scholar
- Houghton, J. T., Callader, B., Varney, S. (eds.), 1992:Climate Change — The IPCC Supplement Report. Cambridge: Cambridge University Press, 200 pp.Google Scholar
- Jones, P. D., 1988: Hemispheric surface temperature variations: Recent trends and an update to 1987.J. Climate 1, 654–660.Google Scholar
- Jones, P. D., Kelly, P. M., 1983: The spatial and temporal characteristics of Northern Hemisphere surface air temperature variations.J. Climatol. 3, 243–252.Google Scholar
- Jones, P. D., Wigley, T. M. L., 1990: Global warming trends.Scientific American 263, 84–91.Google Scholar
- Jones, P. D., Wigley, T. M. L., Wright, P. B., 1986: Global temperature variations between 1861 and 1984.Nature 332, 430–434.Google Scholar
- Jones, P. D., Wigley, T. M. L., Folland, C. K., Parker, D. E., Angell, J. K., 1988: Evidence for global warming in the past decade.Nature 332, 790.Google Scholar
- Karl, T. R., Tarpley, J. D., Quayle, R. G., Diaz, H. F., Robinson, D. A., Bradley, R. S., 1989: The recent climate record: What it can and cannot tell us.Rev. Geophys. 27, 405–430.Google Scholar
- Kirchhofer, W., Sevruk, B., 1992: Mean annual corrections of measured precipitation amounts, 1951–1980. In: Spreafico, M., Weingartner, R. (eds.)Hydrological Altas of Switzerland. Bern: National Topographical Service.Google Scholar
- Müller, H., Kappenberger, G., 1991: Claridenfirn-Messungen, 1914–1984.Zürcher Geographische Schriften, 40, 79 pp.Google Scholar
- Rebetez, M., 1994: Perception du temps et du climat: une analyse du climat de Suisse Romande sur la base des dictons populaires. PhD Thesis, University of Lausanne. Editions Stratus, Oron-la-Ville, 304 pp.Google Scholar
- Rind, D., Goldberg, R., Ruedy, R., 1989: Change in climate variability in the 21st century.Climatic Change 14, 5–37.Google Scholar
- Rohrer, M., 1992: Die Schneedecke im Schweizer Alpenraum und ihre Modellierung.Zürcher geographische Schriften, 49, 178 pp.Google Scholar
- Sevruk, B., Kirchhofer, W., Tihlarik, R., Zahlavova, L., 1993: Precipitation corrections in Switzerland. Proc. Symp. on Precipitation and Evaporation, Bratislava, Slovakia, 155–156.Google Scholar
- Trenberth, K. E., 1990: Recent observed interdecadal climate changes in the Northern Hemisphere.Bull. Amer. Meteor. Soc. 71, 988–993.Google Scholar
- Wallace, J. M., Zhang, Y., 1993: Structure and seasonality of interannual and interdecadal variability of the geopotential height and temperature fields in the Northern Hemisphere troposphere.J. Climatol. 6, 2063–2082.Google Scholar
- Wigley, T. M. L., Jones, P. D., 1981: Detecting CO2-induced climate change.Nature 292, 205–208.Google Scholar
- Wigley, T. M. L., Raper, S. C. B., 1990: Natural variability of the climate system and detection of the greenhouse effect.Nature 334, 324–327.Google Scholar