@article{3017517, title = "Assimilation of radar altimeter data in numerical wave models: An impact study in two different wave climate regions", author = "Emmanouil, G. and Galanis, G. and Kallos, G. and Breivik, L.A. and Heiberg, H. and Reistad, M.", journal = "Annales geophysicae", year = "2007", volume = "25", number = "3", pages = "581-595", publisher = "European Geosciences Union (EGU)", issn = "0755-0685", doi = "10.5194/angeo-25-581-2007", keywords = "air-sea interaction; data assimilation; forecasting method; numerical model; radar altimetry; satellite data; wave climate; wave height, Indian Ocean; Mediterranean Sea", abstract = "An operational assimilation system incorporating significant wave height observations in high resolution numerical wave models is studied and evaluated. In particular, altimeter satellite data provided by the European Space Agency (ESA-ENVISAT) are assimilated in the wave model WAM which operates in two different wave climate areas: the Mediterranean Sea and the Indian Ocean. The first is a wind-sea dominated area while in the second, swell is the principal part of the sea state, a fact that seriously affects the performance of the assimilation scheme. A detailed study of the different impact is presented and the resulting forecasts are evaluated against available buoy and satellite observations. The corresponding results show a considerable improvement in wave forecasting for the Indian Ocean while in the Mediterranean Sea the assimilation impact is restricted to isolated areas." }