Long Series of Data

Cherry Tree
Image: Benjamin Gimmel
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Cherry Tree
Cherry Tree (Image: Benjamin Gimmel)

In Switzerland, several phenological events have been observed in a long tradition and recorded in long rows. Some of the more than one hundred year old series of data are presented here.


Icebreak Data of Lake St. Moritz from 1832 to 2015

Long series of the ice breakup of Lake St. Moritz with Bézier curve fit
Long series of the ice breakup of Lake St. Moritz with Bézier curve fit (Image: Sarah Arnold)
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Long series of the ice breakup of Lake St. Moritz with Bézier curve fit
Long series of the ice breakup of Lake St. Moritz with Bézier curve fit (Image: Sarah Arnold)

Sources

  • Lütschg-Loetscher, O., Hauck, T., Bohner, R. (1954). Die Eis- und Schneeverhältnisse der Oberengadiner Seen insbesondere des St. Moritzer Sees, in Zum Wasserhaushalt des Schweizer Hochgebirges, Vol. I, Part III, Ch. 10, Schweizerische Geotechnische Kommission, Zürich, pp. 1–173. Daten bis 1945
  • Livingstone, D. (1997). Break-up dates of Alpine lakes as proxy data for local and regional mean surface air temperatures. Climatic Change 37, 407–439.
  • Zusammenstellung der neueren Daten. Engadiner Post. Aktualisierungen.

Flowering of the Cherry Tree in Liestal from 1894 to 2015

Long row of cherry tree blossom with Bézier curve fit
Long row of cherry tree blossom with Bézier curve fit (Image: Sarah Arnold)
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Long row of cherry tree blossom with Bézier curve fit
Long row of cherry tree blossom with Bézier curve fit (Image: Sarah Arnold)

Sources:

  • Defila, C. and B. Clot (2001). Phytophenological trends in Switzerland. International Journal of Biometeorology 45, 203–207.
  • Landwirtschaftliches Zentrum Ebenrain und MeteoSchweiz. Aktuelle Beobachtungen.

Leaf Sprouting of the Horse Chestnut Tree in Geneva from 1800 until 2015

Long row of the leaf sprouting of the horse chestnut with Bézier curve fit
Long row of the leaf sprouting of the horse chestnut with Bézier curve fit (Image: Sarah Arnold)
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Long row of the leaf sprouting of the horse chestnut with Bézier curve fit
Long row of the leaf sprouting of the horse chestnut with Bézier curve fit (Image: Sarah Arnold)

Sources

  • Defila, C. and B. Clot (2001). Phytophenological trends in Switzerland. International Journal of Biometeorology 45, 203–207.
  • «Sautière» des Grossen Rats des Kantons Genf und MeteoSchweiz. Aktuelle Daten.

Explanation

  • x-axis: year of observation
  • y-axis: day of the event
  • The solid line represents the smoothed data. The smoothing was done with a Bézier curve

Icebreak on Lake St. Moritz

  • Since the beginning of the series of measurements, the ice on the lake usually disappeared in the second half of May (in 95 years in total).
  • From 1990 onwards, however, Lake St. Moritz presented itself ice-free as early as the end of April or in the first half of May at the latest.
  • The lake has only been free of the ice layer 28 times as early as April.
  • Thus, the lake thaws earlier and earlier over the years.

Eis auf dem St. Moritzersee

Lake St. Moritz during thaw weather

Flowering of the Cherry Tree in Liestal

  • The observed tree in Liestal is a wild cherry tree on the edge of a forest.
  • Its flowering has been repeating quite stably in April since the beginning of the measurement.
  • Since the 1990s, a trend towards earlier flowering dates has been observed.

Links:

Kirschblüten

Cherry Blossoms

Leaf Sprouting of the Horse Chestnut Tree in Geneva

  • The horse chestnut in Geneva develops its leaves much earlier today than was the case 200 years ago. When measurement began the first buds usually burst in April, today the first burst more recently in February or March.
  • This trend is likely to be influenced by global warming, as well as by structural changes and stronger warming in the city of Geneva.

Links:

Rosskastanie Knospe

Bud of a Horse Chestnut in February