A Parametric Model for Tropical Cyclone Waves

One of the major challenges in fully understanding the complex wave fields produced by intense tropical cyclones is having sufficient data to fully define the spatial wave field in such systems. Although the in situ data set is increasing, it is still quite limited and does not cover the full range of possible tropical cyclone parameters. One way to address this problem is to use remote sensing data obtained from satellites. Radar altimeters on such satellites have now been in operation for more than 25 years. Such a data set is used to investigate the wave field within tropical cyclones. The full data set consists of the over flight by an altimeter of a total of 440 tropical cyclones. As such, the data set is the most extensive ever obtained under tropical cyclone conditions. Using this data set, a parametric model for the wave field is developed. The analysis confirms that the most extreme waves are generated to the right (northern hemisphere) of the storm, where the waves generated tend to move forward with the storm. As such, they experience an extended fetch. This concept is used in conjunction with JONSWAP scaling to develop a parametric model which can be used to predict the tropical cyclone wave field. This model is then used in conjunction with in situ data to provide an estimate of the wave spectrum at any point in the spatial wave field. This approach provides a very valuable approach for preliminary design and extreme value studies.