TU Bergakademie Freiberg , Brennhausgasse 14, 09596 Freiberg, Germany
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Transcript of TU Bergakademie Freiberg , Brennhausgasse 14, 09596 Freiberg, Germany
TU Bergakademie Freiberg , Brennhausgasse 14, 09596 Freiberg, GermanyPhone: 0 37 31/39-3533, www.tu-freiberg.de
Spatial response and temporal development (1901 – 2010) of two manual atmospheric
circulation classifications in Europe
Andreas Hoy, Mait Sepp, Jörg [email protected]
ClassificationsGrosswetterlagen (GWLc) Vangengeim-Girs
(VGc)Werner/ Gerstengarbe 2010, updated Bolotinskaya/ Ryzhakov 1964,
updated
- Central Europe/ Germany - NE Europe/ NW Russia- Continental focus (Europe) - Hemispheric focus (Eurasia, Polar)- 29 subtypes; e.g., 10 major types - 3 circulation forms- Minimum persistence of 3 days - No minimum persistence- Here: Westerlies (GWT W, ½ SW, ½ NW) - Here: Westerlies (circ. form W)
EMS, 15.09.2011 [email protected]
W
C
E
Average Frequencies: 1901 – 2010 Anissimov et al. 2010
Spatial Response – Methods
• Correlation mapping of montly sea level pressure averages/ circulation type frequency (via SURFER 9.2.397)
• Goal: visualisation of average distribution of pressure centres (location of cyclones/ anticyclones: negative/ positive correlations)
• Global illustrations (80°N to 80°S) for full spatial response• Sea level pressure: gridded set of monthly averages in 5 x
5° worldwide resolution (Allan/ Ansell 2006) • Focus on highly significant correlations with r≥0.3/ r≤ 0.‑ 3,
α=0.001• Linear detrending of time series to reduce „artificial“
correlations (! subperiodical, polynomial, … trends)
EMS, 15.09.2011 [email protected]
Spatial Response – Conceptual Maps
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Westerlies (W) Easterlies (E)
Northerlies (C)
- GWLc: dark filling - VGc: light filling- borders: if dashed, system is nonexisting in specific months- arrows: direction of inflow in classifications focus region
Temporal Development - Methods
• Relative frequency (%) of circulation types• Time series and linear trends for 1901 – 2010 (yearly, half
yearly)• Annual cycle: 31 day smoothing, 1901 – 2010 vs. climate
normals 1951-1980, 1981-2010• Goal: evaluation of annual/ inner-annual changes in
frequency of atmospheric circulation patterns
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Time Series – GWLc Westerlies
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Time Series – VGc Westerlies
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Annual Cycle – GWLc Westerlies
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Annual Cycle – VGc Westerlies
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Annual Cycle – VGc Westerlies
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Annual Cycle – GWLc Westerlies
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Summary (Westerlies)Spatial response:• Correlation maps illustrate average spatial impact and magnitude of
analysed circulation patterns• Spatial response WHY > SHY in both classifications• Spatial response VGc > GWLc (only WHY), confirming different
conceptual focus• „Teleconnections“ subject of further research
Temporal development:• Trends GWLc: low annually, but inner-annually pronounced• Trends VGc: large fluctuations (circulation epochs?), no use of linear
trends• Time series hardly comparable, but similarities in inner-annual
behaviourEMS, 15.09.2011 [email protected] 14
Spare slides
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Classifications Manually classified Automated classified
Assignment of daily synoptic conditions to one specific circulation form
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• by experienced meteorologists
Disadvantages• No reproducibility• Inhomogeneities (subjectivity of/
and change of executing scientists)
Advantages• Availability of long data series (>100
years) more robust conclusions• Better generalisation of dynamic
processes & adjustment of missing data by human eye
• via numerical methods
Advantages• Limitless reproducibility• No inhomogeneities, if incoming
data are of the same (!) qualityDisadvantages• Shorter time series (most input data
not available before the 1950s)• Missing flexibility through fixed
input parameters
Manual classifications: useful complement to automated classificationsEMS, 15.09.2011 [email protected]
EMS, 15.09.2011 [email protected]: Westerlies (monthly)
EMS, 15.09.2011 [email protected]: Westerlies (monthly)
GWLc Westerlies: moving trend analysis
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