1. Stratosphere resolving Historical Forecast Project
Amy Butler, Adam Scaife, Alexey Karpechko,
Andrew Charlton-Perez, Alan O’Neill,
Natalia Calvo, Maria Athanassiadou,
plus others to be confirmed…

3. Biases in the stratosphere and troposphere

4. NAO in sea level pressure – Hi Top vs Low Top

5. North Atlantic Oscillation (usual definition)

6. Extra winter skill in stratosphere resolving models

7. Extra skill is from ENSO years

8. SHFP activity summary
Seven high top and seven low top models are now in the CHFP
These are being analysed by our WCRP-SPARC colleagues
High top models show higher skill (but this is an ensemble of opportunity)
The differences in skill are apparent in relevant surface quantities
The differences are prominent over the northern extratropics in winter and appear to be related to ENSO teleconnections which are already known to operate via the stratosphere
A paper is in preparation led by Amy – should we add one person from each data providing centre?

9. Surface Northern Annular Mode

10. Mid-troposhere Northern Annular Mode