83rd Annual

Tuesday, 11 February 2003: 8:45 AM
Variability of Marine Surface Fluxes over Shoaling Waves Measured with Air-Sea Interaction Spar Buoys
Hans C. Graber, Univ. of Miami/RSMAS, Miami, FL; and M. A. Donelan and W. M. Drennan
Three air-sea interaction spar (ASIS) buoys were deployed in coastal waters off Duck, North Carolina during the SHOWEX experiment in Fall 1999. The buoys acquired continuous time series of wave elevations using a nested 8-wire gauge array, observations of meteorological variables (wind velocity and stress, atmospheric stability), and near-surface oceanographic variables (near-surface currents and water temperature).

In recent years, there has been considerable effort spent on determining what (if any) effect shoaling waves have on air-sea surface fluxes. This problem has two components: the effect of wave age on fluxes in the absence of swell, and the additional affect of swell. In both situations, a lack of field data combining coincident measurements of direct fluxes and directional wave data has hindered progress.

Here we present recent eddy correlation stress and coincident directional wave spectra from the Shoaling Waves (SHOWEX) field experiment. These data are used to address both aspects of the sea state dependence in shoaling waters. The data are also shown to support a significant dependence of momentum flux on the presence swell. This latter effect is important for low wind speeds ($U < 5$ m/s) and co-linear (or opposing) wind and swell.

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