310 likes | 435 Views
Review of Northern Winter 2011/12 Mike Blackburn National Centre for Atmospheric Science, University of Reading Seasonal Climate Discussion 2 April 2012. NCAS Seasonal Climate Discussion, 2 April 2012. Summary Drivers for global circulation - La Niña, MJO, sea-ice, (stratosphere)
E N D
Review of Northern Winter 2011/12 Mike Blackburn National Centre for Atmospheric Science, University of Reading Seasonal Climate Discussion 2 April 2012 NCAS Seasonal Climate Discussion, 2 April 2012
Summary • Drivers for global circulation • - La Niña, MJO, sea-ice, (stratosphere) • Observed regional anomalies • - UK and European precipitation, windstorms • Large scale circulation • - Teleconnection patterns, Atlantic jet, global anomalies • - Winter onset in Europe • - Eurasian blocking / cold period Jan/Feb NCAS Seasonal Climate Discussion, 2 April 2012
La Niña, 2011/12 SST anomaly DJF 11/12 OLR anomaly DJF 11/12 NOAA Climate Diagnostics Bulletin NOAA ESRL
La Niña, compare with 2010/11 SST anomaly DJF 10/11 SST anomaly DJF 11/12 OLR anomaly DJF 10/11 OLR anomaly DJF 11/12 NOAA ESRL
Tropical variability - atmosphere Active MJO: strongest late Autumn and late Winter NOAA CPC (pentad averages)
MJO activity Oct-Nov 11 (with EC monthly forecasts) Forecast: phase good but amplitude weak in Nov. NOAA CPC
MJO activity JFM12 (with EC monthly forecasts) Last month: eastward propagation well forecast NOAA CPC
Arctic sea-ice extent Maximum sea-ice extent, March 2012 NOAA CPC
Northern Hemisphere Stratosphere Winter 2011/12 • Strong early vortex • Disturbed vortex late Jan / early Feb • 1991-2004 climatology and range Met Office stratospheric analyses, processed at Reading
UK temperature anomaly DJF 2011-12 DJF 11-12 Dec 2011 Jan 2012 Feb 2012 UK Met Office
UK precipitation anomaly (% normal) DJF 2011-12 DJF 11-12 Dec 2011 Jan 2012 Feb 2012 UK Met Office
UK precipitation anomaly (% normal) 2011 Annual 2011 DJF10-11 MAM 2011 JJA 2011 SON 2011 DJF 11-12 UK Met Office
European precipitation anomalies (%) January 2012 DJF 2011/12 February 2012 NOAA ESRL
Early Winter windstorms 3 January, 12 UTC 8 December, 18 UTC Cyclone “Friedhelm” DIAMET flight Extreme gusts, 165 kt, Cairngorm UK Met Office
Early Winter windstorms 3 January, 12 UTC 8 December, 18 UTC Cyclone “Friedhelm” ECMWF analysis
Teleconnection patterns AO Pmsl NAO Z500 PNA Z500 NOAA CPC
Jet streams – DJF 2011-12 Z250 anom DJF 2011-12 NOAA ESRL
Jet streams – DJF 2011-12 Z250 anom DJF climate NOAA ESRL
Jet streams – DJF 2011-12 December January February March NOAA ESRL
Atlantic jet: U850 latitude-time Tim Woollings 1 Dec 2011 10 Mar 2012
Atlantic jet: U850 latitude-time Tim Woollings 1 Dec 2010 10 Mar 2011
Atlantic jet: U850 latitude-time Tim Woollings 1 Dec 2009 10 Mar 2010
Winter onset - 250hPa height (approx) weekly averages: November - December 2011 Nov 04-11 Nov 11-16 Nov 18-23 Nov 25 - Dec 02 Dec 02-12 Dec 09-16 ECMWF analyses, processed at University of Reading
European Blocking : Winter 2011/12 Z250, 55°-70°N (weak throughout December) NOAA ESRL / CPC
Jet streams – Eurasian blocking period 20 Jan to 10 Feb 2012 (Eurasian blocking) 15 Feb to 18 Mar 2012 (Atlantic ridge extends into Europe) NOAA ESRL
250hPa height – hemispheric planetary wave pattern : (approx) weekly averages: Jan – Feb 2012 Jan 06-11 Jan 13-20 Jan 20-27 Jan 27 – Feb 03 Feb 03-10 Feb 10-17 ECMWF analyses, processed at University of Reading
European anomalies – February 05-11 Temperature anomaly Precipitation total • Eurasian blocking, extensive severe cold, fatalities NOAA ESRL