Singularity (meteorology)

The term singularity ( Latin singularis 'unique') describes strange weather cases in meteorology . These are weather conditions that are highly likely to occur at certain times of the year and which represent a significant deviation from a smooth course of the weather elements (temperature, precipitation, etc.), but are within the long-term average. Well-known singularities in Central Europe are, for example, the March winter , the ice saints , the sheep cold , the dog days , the Indian summer , the Martini summer and the Christmas thaw .
The opposite, unforeseen deviations from the mean, is called anomaly ( Greek anómalos , uneven, irregular ').

To the subject

The term singularity was introduced by August Schmauß in the 1920s, since then the research of these regularities in the course of the weather has been called singularity research . Singularity research had reached its peak in the 1940s. The aim was to enable a weather forecast based on these recurring events, but this had to be abandoned. In the 1950s, Franz Baur further developed singularity research to research large-scale weather conditions .

root cause

The cause of this regularity lies in the cyclical course of the sun's position, in temperature changes - also associated with this - and recurring currents ( general weather situation ), which do not disappear even in the long-term average. It should be noted, however, that the occurrence of the singularities on a specific date or time period is also very dependent on coincidences; in addition, these events usually do not even occur in two thirds of all observed years.

Central European singularities

If the investigations by Flohn (1954), Schönwiese (1987), Malberg (1989) and Bissolli (1991) are summarized, the following, statistically easily verifiable, calendar- related temperature peculiarities in Central Europe are obtained.

Period	event	Phenological period	traditional lost days
7th-9th January	Cold snap	-
17th to 20th January	Cold snap	High winter
February 9	Warm air advance	-
February 16	Cold air ingress	Late winter
25th March	Cold snap	March winter	Annunciation (23.)
April 22	Warm air phase	Mid spring
25-27 April	cool weather	-	Georgi (23rd), Markus (25th)
15-20 May	Warm air advance	Late spring
21-23 May	Cold relapse after warm air supply	Ice Saints	Pankraz, Servaz, Bonifaz and the "cold" Sophie (12-15)
3rd - 10th June	Warm air period	Early summer
11-20 June	cool weather	Sheep cold
end of June	Temperature drop after brief heating	Dormouse
9-14 July	first midsummer period	-
22./23. July	cooler weather	-
Late July / early August	second midsummer period	Dog days
beginning of September	warm weather	-
10/11 September	second warm phase	-
Mid September	cooler weather	-
from the end of September	stable fair weather	Indian summer
Mid-October	cool weather	-
Mid November	Heat relapse	Martini summer	Martin's Day (11th)
beginning of December	Cold spell	-
middle of December	Cold spell after previous mitigation	-	Nicholas (6.)
24.-28. December	Thermal breakdown	Christmas thaw
End of December / New Year	Cold snap	-

These singularities primarily represent the alternation of low phases (bad weather) and more stable high pressure influence, with moderate Atlantic air masses temporarily carried by the Gulf Stream (cool in summer, mild in winter) and stronger warming and cooling phases due to oceanic or continental highs, and the seasonal highs Average geographical latitude of the North Atlantic lows , which allow polar cold air or Atlantic- Mediterranean subtropical warm air to flow in on their fronts and backs . They therefore apply primarily to the core of Europe's Atlantic zone of influence .

Superimposed by the North Atlantic Oscillation (NAO) and also longer fluctuations, such as the Atlantic Multi-Decade Oscillation (AMO), these singularities can shift widely over the course of the year in certain years, fail completely or reverse. The model only describes long-term significance.

When referring to lost days , it should be noted that a number of presumably old peasant rules , which typically also represent such singularities (such as the ice saints , or the dormouse day for the cancellation of dog days), would in principle be seen a few days later , taking into account the Gregorian calendar reform , but more recent rules Not. Some of these rules then demonstrably have a certain significance, so they can be seen as protoscientific forerunners of the singularity model, as the naming of some of the events shows.

Web links

Special weather conditions. Meteomedia
Weather singularities. Zeit Online , September 2014

literature

Horst Malberg: Farmer rules. From a meteorological point of view. 4th ext. Edition. Springer, Berlin / Heidelberg 2003, ISBN 978-3-540-00673-2

Individual evidence

^ Schmauss: Singularities in the annual weather pattern in Munich . German Meteorological Yearbook, Munich, 1928

↑ Joachim Blüthgen, Wolfgang Weischet: General climatography. de Gruyter, 1980, ISBN 3-11-006561-4

↑ Peter bite Olli: probability and statistical characteristics of the weather usually cases in the Federal Republic of Germany and West Berlin . Dissertation (= reports from the Institute for Meteorology and Geophysics at the University of Frankfurt am Main . No. 88 ). Self-published by the institute, 1991, ZDB -ID 967715-X .

↑ Horst Malberg: Peasant rules. From a meteorological point of view. 4th ext. Edition. Springer, Berlin / Heidelberg 2003, ISBN 978-3-540-00673-2 , p. 28

↑ Extreme events e.g. 1985, 1997 and 2016

↑ Siegfried Werner: Deciphering weather secrets yourself . Munich 1993, ISBN 3-453-06640-5 , p. 51.

↑ cf. the farmer rules like "St. Nikolaus washes out the banks. ”This rule is from southern Germany (see on haben.at ), meaning rain / thaw floods.