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Case Study of the Cold Air Outbreak from Siberia the Winter 2011/2012

Torén, Frida LU ; Bäckström, Emelie LU and Weidbo, Caroline LU (2012) FYSK01 20121
Department of Physics
Abstract
This is an analysis of how the Siberian High influenced the winter weather in Europe 2011/2012, with focus on Scandinavia and Sweden. Overall, the winter of 2011/2012 was very mild with unusually high temperatures in the entire Scandinavia. In late January however, there was a rearrangement in the large-scale flow pattern and a blocking situation was established over Russia which affected the normal trajectories of the low pressure systems. The change resulted in cold air outbreaks from the major high pressure located over Russia and a cold wave hit large parts of Europe. It brought unusually low temperatures and heavy snowfall to the affected areas, but it lasted only for a short period of three weeks. The cold air outbreak was a result... (More)
This is an analysis of how the Siberian High influenced the winter weather in Europe 2011/2012, with focus on Scandinavia and Sweden. Overall, the winter of 2011/2012 was very mild with unusually high temperatures in the entire Scandinavia. In late January however, there was a rearrangement in the large-scale flow pattern and a blocking situation was established over Russia which affected the normal trajectories of the low pressure systems. The change resulted in cold air outbreaks from the major high pressure located over Russia and a cold wave hit large parts of Europe. It brought unusually low temperatures and heavy snowfall to the affected areas, but it lasted only for a short period of three weeks. The cold air outbreak was a result of the westward movement and intensification of the Siberian High. Before this cold air outbreak the weather was characterized by frequently incoming low pressure systems associated with the baroclinic zone. The displacement of the Siberian High created a blocking pattern over almost entire Europe and prevented the normal westerly flow from the Atlantic. This allowed the cold air from Russia to flow into Europe and the consequences became severe in several countries. There is no definite explanation to the sudden growing and westward movement of the Siberian High the winter 2011/2012 and we can only speculate in why it occurred. There are several possible parameters that could have contributed to the development, for example perturbations in the planetary and synoptic scale flow, the effect of radiative cooling, changes in the phase of the North Atlantic Oscillation and the effect of climate changes. Most likely the event is a combination of these and not a result of one specific parameter. (Less)
Abstract (Swedish)
Detta är en analys av hur det Sibiriska högtrycket påverkade vintervädret i Europa 2011/2012 med fokus på Skandinavien och Sverige. Sammantaget var vintern 2011/2012 väldigt mild med ovanligt höga temperaturer i hela Skandinavien. I slutet på januari inträffade dock en omfördelning i det storskaliga mönstret och en blockering uppstod över Ryssland som påverkade lågtryckssystemens normala banor. Denna ändring resulterade i kalluftsutbrott från det stora högtrycket över Ryssland och en köldvåg drabbade stora delar av Europa. Detta förde med sig ovanligt låga temperaturer och kraftigt snöfall till de drabbade områdena men det varade endast en kort period på tre veckor. Kalluftsutbrotten var ett resultat av den västliga förflyttningen och... (More)
Detta är en analys av hur det Sibiriska högtrycket påverkade vintervädret i Europa 2011/2012 med fokus på Skandinavien och Sverige. Sammantaget var vintern 2011/2012 väldigt mild med ovanligt höga temperaturer i hela Skandinavien. I slutet på januari inträffade dock en omfördelning i det storskaliga mönstret och en blockering uppstod över Ryssland som påverkade lågtryckssystemens normala banor. Denna ändring resulterade i kalluftsutbrott från det stora högtrycket över Ryssland och en köldvåg drabbade stora delar av Europa. Detta förde med sig ovanligt låga temperaturer och kraftigt snöfall till de drabbade områdena men det varade endast en kort period på tre veckor. Kalluftsutbrotten var ett resultat av den västliga förflyttningen och intensifieringen av det sibiriska högtrycket. Innan kalluftsutbrottet karakteriserades vädret av frekvent inkommande lågtryckssystem, associerade med den baroklina zonen. Förflyttningen av det sibiriska högtrycket gav upphov till ett blockeringsmönster över nästan hela Europa som hindrade det normala västliga flödet från Atlanten. Detta gjorde att kalluften från Ryssland kunde ta sig in över Europa vilket fick allvarliga konsekvenser i ett flertal länder. Det finns ingen uppenbar förklaring till den plötsliga tillväxten och den västliga förflyttningen av det sibiriska högtrycket vintern 2011/2012 och vi kan endast spekulera i varför detta inträffade. Det finns flera möjliga parametrar som kan ha bidragit till utvecklingen, såsom perturbationer i det planetära och synoptiska flödet, effekten av strålningsavkylning, ändringar i fasen av den Nordatlantiska oscillationen samt effekten av klimatförändringar. Troligtvis är händelsen en kombination av dessa och inte ett reslutat av en specifik parameter. (Less)
Please use this url to cite or link to this publication:
author
Torén, Frida LU ; Bäckström, Emelie LU and Weidbo, Caroline LU
supervisor
organization
course
FYSK01 20121
year
type
M2 - Bachelor Degree
subject
keywords
Klimatförändringar, strålningsavkylning, kalluftsutbrott
language
English
id
2968140
date added to LUP
2012-09-06 09:49:06
date last changed
2012-09-06 09:49:06
@misc{2968140,
  abstract     = {This is an analysis of how the Siberian High influenced the winter weather in Europe 2011/2012, with focus on Scandinavia and Sweden. Overall, the winter of 2011/2012 was very mild with unusually high temperatures in the entire Scandinavia. In late January however, there was a rearrangement in the large-scale flow pattern and a blocking situation was established over Russia which affected the normal trajectories of the low pressure systems. The change resulted in cold air outbreaks from the major high pressure located over Russia and a cold wave hit large parts of Europe. It brought unusually low temperatures and heavy snowfall to the affected areas, but it lasted only for a short period of three weeks. The cold air outbreak was a result of the westward movement and intensification of the Siberian High. Before this cold air outbreak the weather was characterized by frequently incoming low pressure systems associated with the baroclinic zone. The displacement of the Siberian High created a blocking pattern over almost entire Europe and prevented the normal westerly flow from the Atlantic. This allowed the cold air from Russia to flow into Europe and the consequences became severe in several countries. There is no definite explanation to the sudden growing and westward movement of the Siberian High the winter 2011/2012 and we can only speculate in why it occurred. There are several possible parameters that could have contributed to the development, for example perturbations in the planetary and synoptic scale flow, the effect of radiative cooling, changes in the phase of the North Atlantic Oscillation and the effect of climate changes. Most likely the event is a combination of these and not a result of one specific parameter.},
  author       = {Torén, Frida and Bäckström, Emelie and Weidbo, Caroline},
  keyword      = {Klimatförändringar,strålningsavkylning,kalluftsutbrott},
  language     = {eng},
  note         = {Student Paper},
  title        = {Case Study of the Cold Air Outbreak from Siberia the Winter 2011/2012},
  year         = {2012},
}