| Popis: |
To characterize the turbulence quantities such as vertical momentum fluxes during swell wave conditions, we develop a wave-turbulence decomposition method to split the high-frequency surface wind data into wind and wave time series. By assuming the frozen turbulence field, the method replaces an empirically fitted spectrum to the observed wind spectrum within the wave-affected frequency band. Time series of waves and turbulence are then synthetically generated based on a proposed wind-wave coherence function. Using two days of sonic anemometer wind measurements at 15 m height, the upward momentum transfer could be observed during high-steady (∼ 7 m/s) and decaying wind conditions. The vertical wind spectra show, however, higher energy within the wave frequency bands during low winds, old sea, and stable boundary layer condition. During the high and decaying winds, the atmospheric stability changes between unstable and stable conditions, blurring the wave signals due to the thermally/mechanically generated turbulence. |
