Speaker: Leonel Romero (UCSB)
Title: Distribution of Surface Wave Breaking Fronts
Abstract: This study describes a model of Phillip’s Λ(c) distribution, which is the expected length of breaking fronts (per unit surface area) moving with velocity c to c+dc, providing a framework for coupled atmosphere-wave-ocean models to explicitly account for wave breaking related air-sea fluxes. The model of Λ(c) depends on the spectral saturation, based on the statistics of the lengths of crest exceeding wave slope criteria, including long-wave-short-wave modulation. A wave breaking dissipation function based on the fifth moment of Λ(c) was implemented in the model WaveWatchIII. The wave solutions are consistent with available observations, including several metrics of the spectrum and Λ(c) distributions. The modeled whitecap coverage computed from Λ(c) reproduces recent field observations over a wide range of wind speeds, saturating at high winds. The wave breaking model is validated and tested in conditions with strong wave-current interactions. Wave breaking variability due to wave-current interactions is significant at submesoscales (order 1 km or smaller). The model of Λ combined with a scaling of the equilibrium range of the spectrum gives a simple analytical function that can be used to model the whitecap coverage accurately, reproducing the main features of empirically derived parameterizations. I will discuss potential implications for gas flux budgets and remote sensing ocean color processing.