1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Wave induced Turbulence and Bubbles and their Effect on Radiance in the Upper Ocean

The long-term goal of this project is to measure wave induced turbulence and bubble clouds at a range of atmospheric and oceanographic conditions, covering a wide range of bubble sizes and concentrations, and to investigate their effect on radiance in the upper ocean. This is as a response to the disturbing fact that despite the fundamental importance of optical backscatter in the ocean it is still not possible to explain more than 5 to 10 percent of the particulate backscattering in the ocean based on known constituents even during periods with no active wave breaking (Terrill & Lewis, 2004). An important part of this work is to improve on our understanding of the role of manmade and natural surfactants in modifying the turbulence and bubble fields and therefore ultimately the upper ocean radiance. OBJECTIVES The main objectives of this study where 1) to develop the necessary technology to allow for in-situ measurements of bubble size distributions over a wide range of bubble sizes and with sufficient temporal and air-fraction resolution to investigate the role of bubbles on upper ocean radiance, 2) develop and test methods and algorithms to obtain bubble size distributions from such instrumentation, 3) to make comparisons between different bubble measurement techniques (acoustical and optical) t