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By integrating satellites and in situ measurements in meteorological models, we can determine and forecast the sea state as well as the wave height at a global scale.

See the video Waves forecasting: flash (9 Mo) or mpeg (38 Mo)

Predict wave height is crucial in diverse fields like weather forecasting, coastal planning, maritime safety and shipping. Altimetry satellites measure wave height along track precisely at a given point in space and time. But it can't give a global picture across the oceans. This is why the European Center for Medium-Range Weather Forecasts (ECMWF) at Reading in England, use a model that simulates ocean waves and surface winds. By integrating satellites and in situ measurements in this model, we can determine and forecast the sea state as well as the wave height at a global scale. The more satellites that we use, the close we get the real conditions. Since 1993, the models have become significantly more accurate. The number of measurements has also increased, particularly thanks to Jason-1 and it's now possible to establish reliable forecast in 5 days in advance.

One example is given with the storm in Ireland in December 2007. The extreme conditions of the 9^th of December with 12 meters waves were measured by satellites and buoys. The forecast made 4 days earlier closely reflected the actual weather situation.

An another example: the strong swell developped south of La Réunion in May 2007. The model prediction closely matched  to real conditions. Both in terms of the mean swell as well as the peak swell reach the 10 m.

Now forecast accuracy is set to take a new step forward. Scientists expect to win one day of reliable forecasts every decade particularly by integrating in numerical models the growing number of measurements from altimetry satellites like Jason-2.

Further information:

• Applications : <link internal-link>Atmosphere, winds and waves, <link internal-link>Atlantic storm wave heights at hurricane's level in December 2007, <link internal-link>Southern swell in the Indian Ocean in May 2007.
• Newsletters:
  
  • #4 (1996) <link internal-link>Validating Topex/Poseidon significant wave height. S. Barstow
  • #6 (1998) <link fileadmin documents kiosque newsletter news06 lefevre_uk.pdf download>Altimetry and sea-state forecasting at Météo France, J.M. Lefèvre and al.
• Eumetsat
• ECMWF