Hurricane directional wave spectrum spatial variation in the open ocean

The sea surface directional wave spectrum was measured for the first time i n all quadrants of a hurricane's inner core over open water. The NASA airbo rne scanning radar altimeter (SRA) carried aboard one of the NOAA WP-3D hur ricane research aircraft at 1.5-km height acquired the open-ocean data on 2 4 August 1998 when Bonnie, a large hurricane with 1-min sustained surface w inds of nearly 50 m s(-1), was about 400 km east of Abaco Island, Bahamas. The NOAA aircraft spent more than five hours within 180 km of the eye and m ade five eye penetrations. Grayscale coded images of Hurricane Bonnie wave topography include individual waves as high as 19 m peak to trough. The dom inant waves generally propagated at significant angles to the downwind dire ction. At some positions, three different wave fields of comparable energy crossed each other. Partitioning the SRA directional wave spectra enabled d etermination of the characteristics of the various components of the hurric ane wave field and mapping of their spatial variation. A simple model was d eveloped to predict the dominant wave propagation direction.