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TU Bergakademie Freiberg , Brennhausgasse 14, 09596 Freiberg, Germany

Effects of atmospheric circulation on air temperature in Europe and northern Asia. TU Bergakademie Freiberg , Brennhausgasse 14, 09596 Freiberg, Germany Phone: 0 37 31/39-3533, www.tu-freiberg.de. Andreas Hoy , Mait Sepp, Jörg Matschullat andreas.hoy@ioez.tu-freiberg.de.

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TU Bergakademie Freiberg , Brennhausgasse 14, 09596 Freiberg, Germany

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  1. Effects of atmospheric circulation on air temperature in Europe and northern Asia TU Bergakademie Freiberg , Brennhausgasse 14, 09596 Freiberg, Germany Phone: 0 37 31/39-3533, www.tu-freiberg.de Andreas Hoy, Mait Sepp, Jörg Matschullat andreas.hoy@ioez.tu-freiberg.de

  2. Outline of Research Context • Large increase of air temperature in Europe and northern Asia (Siberia) within 1901-2010 – particularly visible in winter,amplified in recent climate normal (1981-2010) • Regionally diverse warming (cooling) patterns cannot be explained by „global warming“ alone • Warming in most (European) circulation forms (Jones/Lister 2009)  if most of them warm, additional warming should be connected to changes in their distribution • Objectives: • To illustrate changes in circulation type frequency • To investigate the spatial impact of more/less frequent circulation types on air temperature • To define regions mostly affected by circulation changes andreas.hoy@ioez.tu-freiberg.de

  3. E W C Basics: Classifications • Vangengeim-Girs classification (VGc) • Hemispheric-scale approach (here: using of North Atlantic-Eurasian sector) • Three main circulation types (W, E, C) • Large frequency fluctuations, “objective” verification using NAOi • Grosswetterlagen classification (GWLc) • Continental-scale approach (North Atlantic-European realm) • 29 sub-types (Grosswetterlagen), combinable into larger groups • Verification by automated version (SynopVisGrosswetterlagen, SVGc, James 2012) andreas.hoy@ioez.tu-freiberg.de Anissimov et al. 2010

  4. Basics: Mapping • Analysis of daily data (circulation types and air temperature) • TEMP data: gridded set of daily averages in ~1.9 x 1.9° worldwide resolution (Twentieth Century Global Reanalysis dataset) • Calculation of daily air temperature anomalies per grid point for 1901-2010/1981-2010; consideration of annual cycle) • Visualisation of average temperature anomaly fields per circulation type (via mapping program SURFER) andreas.hoy@ioez.tu-freiberg.de

  5. Results: Frequency Changes • Large changes in zonal air flow: strong increase of westerlies/decrease of easterlies (1981-2010 vs. 1901-2010); • Comparably small/ambiguous changes in meridional air flow • W, positive NAOi: westerlyinflowintomostof Europe • W#: westerly/north-westerly, E#: easterly/south-easterly inflow into Central E.) Vangengeim-Girs (VGc), NAOi Grosswetterlagen (GWLc/SVGc) andreas.hoy@ioez.tu-freiberg.de

  6. Results: Air Pressure Maps – Westerlies • Sea level pressure patterns; centres of action L L H H W (VGc) W# (GWLc) L L H H NAOi + W# (SVGc) andreas.hoy@ioez.tu-freiberg.de

  7. Results: Temperature Signals – Westerlies W (VGc) L H L H NAOi + andreas.hoy@ioez.tu-freiberg.de

  8. Results: Temperature Signals – Westerlies L H W# (GWLc) L H W# (SVGc) andreas.hoy@ioez.tu-freiberg.de

  9. Results: Air Pressure Maps – Easterlies • Sea level pressure patterns, centres of action H H L L E (VGc) E# (GWLc) H L H L NAOi - E# (SVGc) andreas.hoy@ioez.tu-freiberg.de

  10. Results: Temperature Signals – Easterlies H L E (VGc) H L NAOi - andreas.hoy@ioez.tu-freiberg.de

  11. Results: Temperature Signals – Easterlies H L E# (GWLc) H L E# (SVGc) andreas.hoy@ioez.tu-freiberg.de

  12. Results: Temperature Changes and Circulation • Strong warming in Russia/moderate warming in Western and Central Europe in agreement to increasing westerlies (warm)/ decreasing easterlies (cold) • Regional cooling in Greenland/ eastern Mediterranean connected to rather northerly inflow during westerlies Winter 1981-2010 compared to 1901-2010 andreas.hoy@ioez.tu-freiberg.de

  13. Conclusions • Distinct impact of atmospheric circulation on air temperature  changes in circulation type frequency naturally lead to changes in average air temperature • In winter, westerlies largely increased/easterlies largely decreased in European/northern Asian realm • Besides general warming, frequency shifts agree with large-scale warming pattern in most of northern/central Eurasia • Regional (weak) cooling fits very well to detected frequency shifts andreas.hoy@ioez.tu-freiberg.de

  14. Spare: Centres of Action W# (GWLc) W (VGc) N# (GWLc) C (VGc) E# (GWLc) E (VGc) S# (GWLc) NAOi andreas.hoy@ioez.tu-freiberg.de

  15. Spare: Signal Stability (December) W (VGc)1901-2010 W (VGc)1981-2010 W (VGc)Difference andreas.hoy@ioez.tu-freiberg.de

  16. Spare: Change Signal by Region andreas.hoy@ioez.tu-freiberg.de

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