Evaluation of surface wind fields for prediction of directional ocean wave spectra during Hurricane Sandy

The spatial and temporal distribution of bulk wave parameters are different for each wind field. The WRAMS wind field produces wave model predictions in the best agreement with significant wave height observations, followed by the GAHM and H80 wind fields, with mean correlation coefficients of 0.91, 0.82 and 0.75, respectively averaged over 9 sites. The directional wave spectra for Hurricane Sandy was bi-modal predominantly in the two left quadrants of the hurricane, in agreement with buoy observations. The results indicate that a regional atmospheric wind model that has the best description of the wind field is the most appropriate forcing for hindcasting hurricane waves when detailed observations are available. However a parametric vortex model that incorporates wind at multiple isotachs results in very good agreement with wave observations when used in the wave model, and is a useful too for forecasting hurricane sea surface conditions. The results of this study are relevant for other tropical cyclones that undergo extratropical transition or are influenced by other atmospheric disturbances at mid-latitudes, resulting in storms with large spatial size and high asymmetry.