deletions | additions       diff --git a/observations.tex b/observations.tex  index d0a3b88..97c7883 100644  --- a/observations.tex  +++ b/observations.tex 
...
\end{equation}  In the literature of Monahan and Lu, in 1990, there are two stages in the evolution of whitecaps. In stage A the foam is generated by actively breaking waves, where bubbles are entrained and fragmented inside the breaking wave crest, and is also refered as the acoustically active phase \cite{Deane_Stokes_2002}. In stage B whitecaps are subjects to the decaying foam patches, where bubble creation processes cease, therefore the newly formed bubble plume becomes acoustically quiescent and evolves under the influence of turbulent diffusion \cite{Deane_Stokes_2002}. During the quiescent phase, one can quantify the decay time of whitecap foam by using a simple exponential model implemented by Callaghan et al. in 2012:   \begin{equation}  A(t) = {A}_{0}\exp(\frac{-t}{\tau}, {A}_{0}\exp({-t}\{\tau}),  \end{equation} where $A(t)$ is time evolving area of whitecap foam during the decay phase, $t$ is time where $t=0$ occurs at the time when the foam patch area is at its maximum value, ${A}_{0}$, and $\tau$ is a constant called whitecap foam decay time.  According to Philips, in 1985, to obtain the whitecap fraction, one can refer to an average bubble persistence time $\tau_{bub}$ to obtain $W$:  \begin{equation}