Waves and Climate Change in the North-East Atlantic

by Judith Wolf and David K. Woolf

Presented by: Irma Caraballo Álvarez

October 4, 2012

Introduction

Wave models

Results

Discussion

Outline

Wave height increase Last 25 years Up to 14m in January 1993 Observed by

Buoys Ships Satellite altimetry

TOPEX/Poseidon

Introduction

North Atlantic Oscillation (NAO)

Icelandic Low

Azores High

+NAO

Stronger westerlies

Introduction

Introduction

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

Possible reasons

Increase in winds

Increase in storminess

Storminess variations in decadal scales

Introduction

Usefulness

Interpret data

Study impacts of climate change

Investigate physical explanations

Extrapolate the model

Wave Models

Wave Models

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

Data ECMWF ERA-40 re-analysis model, January

1993 NCEP/NCAR re-analysis model

Validation TOPEX/Poseidon Buoys

Wave Models

Variables

Strength of the westerlies

Frequency of storms

Intensity of storms

Strom tracks

Storm translation speeds

Wave Models

Wave Models

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

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.

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.

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?

Discussion

The End