Effect of high spatial and temporal resolution of the wind field on the evolution of the wave field in a hurricane

Abstract

<p>It is generally accepted that the typical average wind field in a hurricane is well described by a parametric Holland model. The spatial distribution of winds can be determined from data provided by the National Hurricane Center with a 6-hour regularity. The wave field can be calculated by a numerical model from the temporal interpolation of these wind fields. However, a characteristic of wind fields calculated by parametric models is that their spatial and temporal variability are relatively smooth compared to wind fields computed by a high-resolution dynamic model, such as the HWRF. This study analyses the effect of the high temporal and spatial variability of the wind field in a hurricane and its effect on the variability of the wave field calculated by the third-generation wave model Wavewatch III. The wind fields obtained from the use of the HWRF model correspond to the simulation of Hurricane Isaac while crossing through the Gulf of Mexico between 27 and 29 August 2012. The wind fields have a spatial resolution of approximately 2 km and a temporal resolution of 15 minutes. This information is used by an implementation of the Wavewatch III model in the Gulf of Mexico to obtain wave fields with a spatial resolution of 2 km and a temporal resolution of 15 minutes. We find that, despite the high temporal and spatial variability, the mean wind field has a spatial pattern similar to that described by the parametric models. In contrast, the wave field computed by the wave model is much more stable and has a typical structure already described in other studies: large values of significant height in the region of the first quadrant of the hurricane and at the front of its path, with maximum values at distances between one and two times the radius of maximum winds. Smaller values of significant height are found behind the hurricane's track, especially in the third quadrant. The structure of the wave field is largely determined by the translation speed of the storm and the extended fetch effect in the quadrants to the right of the hurricane's path.</p>