Adrian Matei edited observations.tex  about 10 years ago

Commit id: 09a0c11484d77b065818619bfea05db28de9d028

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Usually, a purely geostrophic horizontal wind at sea surface cannot inject enough turbulence to generate wave breaking. Therefore, a downward ageostrophic component or a shift from the purley geostrophy in the wind at sea surface should be present. The wave-driven supergeostrophic jet subdues the downward ageostrophic component (and enhances the upward ageostrophic component or the upward momentum flux), thus it reduces turbulent injection from atmosphere to ocean. The surface value of this wave-driven jet or stress can be described by integrating the wave-induced stress going into each wave component:  \begin{equation}  \tau_{w}\left(0 \right) = \int_{0}^{\infty}\rho_{w}\omega\beta\phi(\omega)d\omega,   \end{equation} where $\omega$ is the wave angular frequency, $\phi(\omega)$ is the frequency spectrum, and $\beta$ is the dimensionless wave growth parameter. \section{Research approaches and methods}   In this section, our scientific objectives and the specific instruments from which we got the date that we will process are presented.   The first basic objective is to detect the temporal behaviour of bubble plumes. Thus, we will make a time evolution of bubble plumes per each wave-breaking event, and produce a mean over all observed wave-breaking events. The sonar data will be used to perform these calculations.   Next, we will assess how variability in bubble plumes depth affects the whitecap time decay. For instance, we will be able to check if a fast decrease in bubble plumes depth influences the longevity of whitecap fractions. To support this correlation between whitecap fractions time decay and bubble plumes dynamics we will use data collected by the sonar and the foam camera.   There was already mentioned that the primary source for whitecap production and variabily is the existence of bubble plumes, therefore our intention is to make direct correlations between bubble plumes and other factors like wind speed and sea state. If we can verify and understand these direct correlations, than we will check the validity of a dynamical relation between bubble plumes and whitecap production. Considering this fact, we want to see how the depth of bubble plumes change with sea state. Thus, we will correlate these changes in bubble plumes depth with different wave states, like wave frequency spectrum and wave amplitude. We want to analyze this bubble plumes dynamics during wind driven waves, which are slower than the environmental wind speed, have higher frequencies and lower amplitudes, and during swells, which are affected by wind history, are faster than the environmental wind speed, have lower frequencies and higher amplitudes.