Optical measurement of the geometry of short wind driven waves

Wind and waves drive the exchange of gases, heat, and momentum between the air and sea in processes that are strongly correlated with the surface geometry. Since surface geometric properties are themselves correlated with remotely measurable parameters (such as the backscatter coefficient), air-sea interactions can be studied using instruments deployed on satellites to provide data with global coverage. However, the current lack of detailed surface geometric data leads to the reliance upon questionable assumptions needed to connect backscatter with air-sea flux processes. To help resolve these questions, we're developing a new instrument to measure the surface geometry in detail using refraction of light at the air-water interface. We present initial results from our instrument showing elevation maps of short wind driven waves with sub-millimeter resolution. We anticipate that this data will help enhance models of the sea surface reflectance and improve remote sensing techniques over oceans.