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Temperature and precipitations rates show characteristic changes during a glacial-interglacial cycle (fig.1). In the middle of a warmer, interglacial period (e.g. Riss/Würm Interglacial), temperature reaches maximum values. Precipitation rates reach their maximum values at about the end of an interglacial period. In the middle of cold, glacial periods, temperature reaches its minimum values whereas precipitation rates reach minimum values at the end of a glacial period. |
1 - Temperature and precipitation deviation of a typical glacial-interglacial cycle (re-drawn after Burga & Perret, 1998). |
| These cycles led to Würm Maximum (18’000-20’000
years BP), the time period of maximum glacier advances in the Alps and the
Northern Lowlands. Wide areas of Switzerland were covered with glaciers
(fig. 2). The mean annual temperature in Switzerland was about -12°C
below today’s mean annual temperature (fig. 3). |
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2 - Glaciated area in Switzerland during Würm Maximum (bold lines show glacier border lines) |
3 - A comparison of mean annual temperatures in Switzerland during the Würm Maximum and today. |
Temperature also fluctuated within glacial periods: during Würm glacial, several warmer interstadial periods occurred. Two interstadial periods during late Würm glacial are particularly well known: the Bölling (13 000 – 12 000 years BP), and Alleröd (12 000 – 11 000 years BP) Interstadial, preceeded by the colder period, Oldest Dryas (18 000 – 13 000 years BP), and succeed by another, colder period Younger Dryas (11 000 - 10 000 years BP). In the Alps, different lat Würm glacier stages (stadials) can be distinguished: Gschnitz (ca. 14 500 years BP), Bühl, Steibach and Daun (ca. 13 000 years BP), Clavadel (ca. 14 000 years BP) and Egesen (ca. 11 000 – 10 000 years BP). |
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Click on the late glacial periods in the following figure to get more information on temperature and vegetation in the Alps and Northern Lowlands. |
4 - Temperature and vegetation variations during late glacial periods |
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29 August 2011 |
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