Retrieving Hurricane Wind Speed From Dominant Wave Parameters

Abstract

One of the most difficult issues in wind measurement using microwave radar is the decreased or loss of sensitivity of the return signal in high winds. Recent analyses of wind speed, wave height, and wave period data from hurricane hunter missions show that surface waves inside hurricanes adhere to the nature of fetch- and duration-limited wind wave generation. Making use of this property, the hurricane wind speed is retrievable from the dominant wave parameter (significant wave height or dominant wave period) using the fetch- or duration-limited wave growth function. An algorithm based on such consideration is developed and applied to two hurricanes of different strengths (categories 2 and 4). The retrieved wind speeds are in good agreement with the reference wind speeds from hurricane hunter measurements. For example, combining the two hurricanes the regression statistics of the bias, slope of linear fitting, root mean squares difference, and correlation coefficient of wind retrieval from significant wave height are 0.50 m/s, 1.01, 4.03 m/s, 0.87 using the fetch-limited wind wave growth function. The range of wind speeds in the combined data is from 22.4 to 65.4 m/s, and there is no indication of saturation problem in the wind retrieval using the dominant wave parameters.