Presentation by Irma Caraballo Alvarez

1. Waves and Climate Change in
the North-East Atlantic
by Judith Wolf and David K. Woolf
Presented by: Irma Caraballo Álvarez
October 4, 2012

2. Outline
 Introduction
 Wave models
 Results
 Discussion

3. Introduction
 Wave height increase
 Last 25 years
 Up to 14m in January 1993
 Observed by
 Buoys
 Ships
 Satellite altimetry
 TOPEX/Poseidon

4. Introduction
 North Atlantic Oscillation (NAO)
 Icelandic Low
 Azores High
 +NAO
 Stronger westerlies

5. Introduction
Figure 1. NAO from NOAA (http://www.climatewatch.noaa.gov/wp-content/uploads/2011/03/ao-nao2_pos_vs_neg.jpg).

6. Introduction
 Possible reasons
 Increase in winds
 Increase in storminess
 Storminess variations in decadal scales

7. Wave Models
 Usefulness
 Interpret data
 Study impacts of climate change
 Investigate physical explanations
 Extrapolate the model

8. Wave Models
Figure 2. Mean atmospheric conditions for January 1993. Coloured shading/contours is wind speed
in m/s, arrows indicate direction of flow.

9. Wave Models
 Data
 ECMWF ERA-40 re-analysis model, January
1993
 NCEP/NCAR re-analysis model
 Validation
 TOPEX/Poseidon
 Buoys

10. Wave Models
 Variables
 Strength of the westerlies
 Frequency of storms
 Intensity of storms
 Strom tracks
 Storm translation speeds

11. Wave Models
Figure 3. Idealized storm with maximum wind speed 10m/s.

12. Wave Models
Table 1. Features of the Storm Varied in the Experimentsa.
Feature Low Medium High
Frequency (month -1) 3 6 9
Intensity (m s-1) 10 15 20
Relative Strength 0.5 1 1.5
Direction ENE NE NNE
Speed (km h-1) 25 50 100
aValues in bold are the "standard" case.

13. Results
Storm frequency
Storm intensity
Relative strength of westerlies
Storm track
Storm translation speed
Figure 4. Effects of the variables on wave height.
Red crosses = monthly maximum, blue squares = monthly mean.

14. Discussion
 Is it possible to predict storms using this
model?
 Can the model be used in other regions?
 Is NAO and storm frequency related to
global warming?

15. The End