1. Jennifer Catto Supervisors: Len Shaffrey and Kevin Hodges Extra-tropical cyclones in HiGEM

2. Outline Compositing and lifecycles Methodology Results Vertical Structures Conclusions so far HiGAM SST experiment Motivation Scientific questions Method

3. Composite Analysis - Methodology Step 1: Identify tracks using Kevin’s tracking program

4. Composite Analysis - Methodology Step 2: Choose at what stage in the lifecycle to composite the tracks e.g. Maximum tendency Maximum intensity Maximum precipitation Minimum pressure and identify where this occurs

5. Composite Analysis - Methodology Step 3: Extract the 20 o radius around this point and note the direction of propagation of the storms.

6. Composite Analysis - Methodology Step 4: Rotate these areas to the same direction of propagation and average them. + + =

7. Composites Analysis – Positions of tracks HiGEM1.2 HadGEM1.2

8. Composites Analysis – Wind, pressure and temperature for Atlantic HadGEM1.2 HiGEM1.2 Colours – wind speed (m/s)

9. Composites Analysis – Wind, pressure and temperature for Atlantic HiGEM1.2 Colours – wind speed (m/s) ERA-40

10. Composites Analysis – Vertical Velocity for Atlantic HadGEM1.2 HiGEM1.2

11. Composites Analysis – Vertical Velocity for Atlantic HiGEM1.2 ERA-40

12. Composites Analysis – Differences between Atlantic and Pacific Pacific Atlantic

13. Lifecycles - Methodology t=0

14. Lifecycles – Results Atlantic Solid lines – HiGEM Dashed lines – HadGEM Dot-dash lines – ERA-40

15. Lifecycles – Results Pacific Solid lines – HiGEM Dashed lines – HadGEM Dot-Dash lines – ERA-40

16. Vertical Structures - Atlantic HiGEM1.2

17. Vertical Structures HadGEM1.2

18. Conclusions so far Storm structures in HiGEM1.2 compare better with ERA- 40 than those in HadGEM1.2 The resolution has a large effect on the maximum intensity that storms attain. Differences between Atlantic and Pacific picked up well by both models.

19. Future Work – HiGAM SST experiment – Motivation 1 HiGEM1.2 HiGAM1.2 Track Density

20. Future Work – HiGAM SST experiment – Motivation 2 HiGAM - HiGEM HiGEM1.2 – ERA-40 Track Density Difference

21. Future Work – HiGAM SST experiment – Motivation 3

22. HiGAM SST experiment Questions: Is it the tighter SST gradient in the Kuroshio current that causes the excess cyclones in the Pacific basin in HiGEM? What effect do the higher resolution SSTs have on the storms in HiGAM? Is there any effect on the storm structures? Method: Include a constant DJF SST anomaly in the midlatitude Pacific Ensemble of 20 simulations beginning in October

23. HiGAM SST experiment - Method HiGEM1.2 HiGAM1.2 Track density plots showing densities associated with genesis in different regions. Will allow us to identify which (if any) storms are affected by changes in SSTs applied to the model.