Upper Meter Processes: Short Wind Waves, Surface Flow, and Microturbulence

Abstract : The primary goal of this project was to advance the knowledge of small-scale air-sea interaction processes at the ocean surface, focussing on the dynamics of short waves, the surface flow field and the micro-turbulence. Since ground truth of the sea surface is still widely missing, a better understanding of the physics of these upper meter processes is of very important for the study of air-sea gas and momentum exchange and the electromagnetic backscatter from the sea surface. This objective was achieved through the development and use of novel experimental methods-based on optical imaging techniques-to measure short wind waves, the turbulence, and the surface flow field at the ocean interface. Within the framework of this project, we developed a drifting buoy with an imaging wave slope gauge (ISG) and an infrared imaging system (CFT). This system allows for the simultaneous measurement of the surface wave slope and the microscale temperature fluctuations within the same foot print. The area extended data from these instruments are combined with meteorological ground truth to obtain a better insight into the dynamics of the interaction between short wind waves with the turbulent drift layer at the ocean surface. Wave slope image data were recorded in the field and compared to the available laboratory data.