Nowcasting ocean surface currents

Madeleine Cahill

19 June 2008

Wealth From Oceans

2. June, 2007

• Velocities in excess of 1.5m/s observed just north of NW Cape

• much greater than speeds associated with mesoscale processes in the region

• appear to be related to small-scale vorticies O(20km)

3. Analysis height map and geostrophic velocities May 21 2008

• map of total height

• Infer velocities assuming geostrophy

4. Available height data

• Time and location of available height data can be limiting

5. Height anomaly map May 21,2008 using altimeter and tidegauge height

• High along track resolution but large distances between tracks - determines the length scale of the mapping

• Mapping is constrained at the coast with the tidegauges

6. Height anomaly map including MCC vectors from SST

• Including MCC vectors from Ian Barton

7. 1 day composite SST May 22, 2008

• MCC vectors are associated with northward intrusion of cold water

8. Now add mean height – Ken Ridgway and Andreas Schiller

OFAM – global model, 0.1° resolution in this region.

Bluelink

OFAMFusion

9. May 21 2008 height and geostrophic velocities

10. Right now, June 17, 2008

• Similar conditions to 2007

but small vortex doesn’t appear to be spinning

11. Fusion – OFAM mean

12. Fusion – BRAN

Thank you

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