Source regions

low-pressure system above the north atlantic
low-pressure system above the north atlantic
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low-pressure system above the north atlantic
low-pressure system above the north atlantic

The importance of the North Atlantic

The amount and origin of the moisture that is transported to Switzerland depends on large-scale atmospheric circulation and the resulting winds. As shown in Figure below, about 40% of the precipitation that falls in Switzerland is evaporated from the North Atlantic. Another 25% comes from the Mediterranean, 20% from the land surface of Central Europe, and 15% from the North and Baltic Seas. However, these figures can vary significantly depending on the season. In winter, the North Atlantic contributes an even greater proportion of moisture, while in summer the Central European land area plays a more important role than is shown in the illustration. In addition, the Alps act as a weather divide, often preventing the transport of moisture from one side of the mountains to the other. Thus, southern Switzerland receives most of its moisture from the Mediterranean while northern Switzerland gets it from the northern seas. In general, the source regions for moisture change significantly throughout the year. This doesn’t necessarily affect the total annual rainfall in an area, however.

Switzerland’s moisture sources, 1995-2002 (after Sodemann et al., 2010).
Switzerland’s moisture sources, 1995-2002 (after Sodemann et al., 2010).
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Switzerland’s moisture sources, 1995-2002 (after Sodemann et al., 2010).
Switzerland’s moisture sources, 1995-2002 (after Sodemann et al., 2010).
Wasser in der Schweiz
  • 2017

Wasser in der Schweiz

Wasser ist in der Schweiz selten knapp und meistens gesundheitlich unbedenklich. Durch neue Konsummuster, die Klimaänderung und energiepolitische Entscheidungen verändern sich sowohl die Verfügbarkeit wie die Nutzung des Wassers.

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1868 – das Hochwasser, das die Schweiz veränderte
  • 2018

1868 – das Hochwasser, das die Schweiz veränderte

Im Herbst 1868 waren Teile der Schweiz von schweren Hochwassern betroffen. Die Bewältigung der Schäden, die Verwaltung der Spenden und die Frage, wie sich solche Ereignisse in Zukunft verhindern lassen, waren für den jungen Bundesstaat eine Herausforderung. Und sie stellten Weichen für den künftigen Umgang mit Naturkatastrophen.
Tal Gletscher

Climate change and Hydrology

The total water supply in Switzerland will change only slightly over the next century. However, the seasonality of precipitation will change, with more precipitation falling during the winter and less during the summer.