North Atlantic low
The low pressure areas in the North Atlantic are called the North Atlantic Low , often only briefly Atlantic Low .
Basics
North Atlantic lows are of great influence for the weather in Europe , as they lead to bad weather in Europe from North America in the subpolar west wind belt across the Atlantic. They are controlled by the action centers of the Azores high , the North Pole high and their intensity and position changes in the course of the North Atlantic Oscillation . Atlantic lows can become very strong and lead to storms or hurricanes .
These low pressure systems - with their cold and warm fronts - usually have an expansion of the order of magnitude of around 1000 km (e.g. from Central Europe ), but can be up to 3000 km thick and then have an impact on the weather for all of Europe.
Classification according to the train path
Depths that have an impact on the weather in Central Europe are divided into those of the Jutland type , the Skagerrak type or the Scandinavia type according to the trajectory ( trajectory of the deep core) . This corresponds to the train routes IV, II and III to Bebber . As a storm low, they generate storm surges on the Central European coasts.
The other more frequent train route is the train routes off the Scandinavian west coast to the northeast (I to Bebber). A less frequent orbit leads via France to the southeast, where these lows become the Mediterranean low (V after Bebber). Another, rare and therefore mostly uncategorized case is the almost mid-Atlantic train path to the Iberian Peninsula ( deep in the south-west of Europe ).
Jutland type
The term Jutland type is used to denote lows that form over Newfoundland , across the Central England and then the North Sea to the east or south-east, and then cross the 8th degree of longitude in the Jutland area between 55 ° and 57 ° north latitude . These lows migrate into the Baltic Sea region . More rarely do they move south to Poland via northern Germany . They typically transform into harmless rain fronts in the Baltic States .
Such storm lows are usually quite small, but can reach enormous wind strengths for a short time. They are able to generate storm surges even at times of low tide and are responsible for the most devastating storm surges on the North Sea coast. Due to the rapid relocation of the low pressure area, low pressure areas of the Jutland type were very difficult to predict for a long time. As a result, the corresponding weather warnings could only be issued at a time when the storm field of the low reached the region to be warned. This had devastating consequences for the Adolph Bermpohl hurricane as well as the Hollandorkan of 1953 , which is related to the Jutland type, and the hurricane Quimburga in 1972, as all three hit the region unprepared and no security measures were possible. Even today, such storms can cause problems in forecasting, according to the extremely fast moving storm Herwart in autumn 2017.
Storm surges that were triggered by the Jutland type are the storm surge of 1976 (Capella storm) with the highest measured water levels on the German North Sea coast in the 20th century, the Adolph Bermpohl storm of February 23, 1967, the Skane storm of October 1967 and also the floods of 1938 and 1949 , and probably also the Burchardi flood of 1634, for example .
Skagerrak type
The Skagerrak type traverses west-northwest to east-southeast over the central North Sea and the Skagerrak (57 ° to 60 ° north at the 8th degree of longitude) into the Baltic Sea region and the Baltic States or Central Eastern Europe.
This type builds up slowly, but together with the tide creates most of the severe storm surges in north-west Central Europe. It is considered to be very predictable.
The storm surges in 1906 , January and February 1916 , 1926 , both October floods in 1936 and the storm surge in 1973 fall into this group .
The Scandinavian type is the name given to the lows that form over the area of Greenland and Iceland and move south-east across the North Sea . You cross the 8th degree of longitude around 60 ° to 65 ° north and move from there over central Scandinavia to the Baltic Sea region and the Baltic States.
These storm lows are less intense, but long-lasting and extensive and can cover the entire south-western North Sea coast with storm surges of varying magnitude, which also extend in waves over several tides.
An example of a storm surge that was triggered by the Scandinavian type is the 1962 storm surge , which flooded parts of Hamburg, among other things. The events of 1911 , 1976 (the later one) and 1981 were of this type as well.
Designation according to the location
During the course, the lows in synoptic meteorology (weather forecasts, weather event analyzes and the like) are usually referred to as the location of the core, as general weather conditions :
- Newfoundland Deep : Deep core off the North American coast off Newfoundland . These lows are mostly formed there on the polar front, migrate from the polar region of Alaska, or are undeveloped or processed Atlantic hurricanes that originally came from the mid-Atlantic off North Africa. They are consistently shifting towards Europe and are mostly well developed due to the long way across the sea (example: Kyrill 2007)
- Iceland deep : Location around or south of Iceland : This is where the Newfoundland deep enters European weather conditions, or a newer deep core emerges in the area to the east of Greenland. However, the Icelandic Depression is not yet directly determining the weather - except for the extreme northwest or when it is extraordinarily large. However, it already acts as a center of action for the large-scale wind flows over northern, western and central Europe, and controls polar cold air , Atlantic humid air masses or southwestern warm air over the mainland. Most of the other layers develop from the Icelandic Depression.
- North Sea Depth : If the Iceland Depression then takes railways of the Jutland, Skagerrak or Scandinavian type to the southeast, when approaching the mainland one speaks specifically of a low over the North Sea . Here it is already determining the weather for all of Northwestern and Central Europe, as its fronts move across the country.
- Deep over the British Isles : An Icelandic low shifted southwards, or a core in the British Isles area that has moved directly across the free Atlantic. These lows often remain stationary for a longer period of time and are already weather-effective as far as the northern Mediterranean
- Scandinavian low: AnIcelandic low or a north-east migrated British lowover Scandinavia . These typically move either over the south (Jutland, Skagerrak or Scandinavian type), or the north of Scandinavia (I after Bebber), where they are no longer weather-effective for Central Europe.
- Deep above the Bay of Biscay : a rarer case of a deep depression extending far south across the Bay of Biscay , which can cause extremely violent storms. Moves east to northeast over northern France and Germany ( Central Europe low , e.g. Lothar 1999), or over southern France, and changes to the Mediterranean low (e.g. Klaus 2009)
Atlantic lows then mostly end as the Baltic Sea lows and / or low over the Baltic States , where most of the regular train tracks between the Alps / Carpathian massifs and the Scandinavian mountains are concentrated, less often over the White Sea or in the Mediterranean region. There they typically disintegrate when they come under the influence of the Eurasian-continental centers of action between the Black Sea and Siberia, or they transform into the lower classes of Eastern Europe.
Examples of Atlantic hurricane and storm lows
- Xynthia , hurricane depth 26. – 28. Feb 2010
- Daisy , storm depression 8-11. January 2010, heavy snowdrifts, storm surge on the Baltic coast
- Emma , hurricane February 29–2. March 2008, as strong as Paula
- Paula , storm depression 26.-27. January 2008, with hurricane force in Austria greater damage than Kyrill and Lothar
- Tilo , hurricane November 9, 2007, with storm surges on the North Sea
- Kyrill , hurricane low January 18, 2007, which led to severe devastation in Central Europe and in some cases even reached hurricane strength , total damage estimated at 10 billion US dollars
- Lothar , Hurricane Depression 1999: similarly expensive as Daria , heaviest wood damage
- Vivian , hurricane low 1990, USD 4 billion insurance damage, top gusts of up to 285 km / h
- Daria , Hurricane Low 1990, one of the worst storms in recent history with over $ 6 billion in insurance damage
See also
- List of weather events in Europe
- Category: Hurricane , with further storm lows with exceptional events
- Assignment of names for weather events
Web links
proof
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↑
Sabine Mertsch: Risk management as a concept for risk reduction using the example of Schleswig-Holstein's areas at risk of flooding . German Committee for Disaster Risk Reduction V., 2004, Section 2.2.1 Definition, origin and frequency of storm surges , p. 12 ( pdf ( memento of the original from January 11, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original - and archive link according to instructions and then remove this note. , dkkv.org).
Christian Kubat: Storm surges on the North Sea coast . Student thesis 2009, GRIN Verlag, 2012, ISBN 978-3-656-09909-3 , pp. 5./6 ( limited preview in the Google book search).
- ↑ a b c Examples according to Kubat: Storm surges .
- ↑ J. Ehlers: The North Sea . 2008, p. 43. Information according to Kubat: Sturmfluten , p. 6.
- ↑ This special case of cold air flowing in from the south-east as a rare special case is specifically described by Heinrich Faust: The structure of the earth's atmosphere: a summary presentation including the new rocket and satellite measurement results . Volume 127 of Die Wissenschaft , F. Vieweg, Braunschweig 1968, p. 68 ( limited preview in the Google book search).
- ↑ The individual layers cannot be found in every large-scale weather system
