1. Greenland / Atlantic blocking is a strong NAO- flow regime Woollings et al (2008, JAS; 2010, JCLIM)

3. Thanks to Giacomo Masato Blocking frequency anomalies this year… … and last year Minor Major

4. Early December: Stratosphere leads blocking over both Greenland and Alaska? Early February: Blocking over Europe contributes to wave activity disturbing vortex? Woollings et al (2008, JAS, QJ; 2010, JGR)

5. Nov – Dec 2009Jan - Feb 2010 Woollings et al (2008), JAS Similar behaviour but different phase…?

6. Open solar flux – measures magnetic variations and correlates well with TSI. Also correlates with detrended CET. Lockwood et al (2010), ERL – out tomorrow! A Solar Contribution?

7. Solar signal NAO

8. Solar signal This winter

9. MODIS 7 JAN 2010 Blocking this year also fits the solar signal

10. Cold temperatures in tropical lower stratosphere in December. Due to QBO (+ solar …?). 1SD of QBO in multiple regression (Crooks and Gray 2005)