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Proceedings Paper

Optical methods for study of sea surface roughness and microscale turbulence
Author(s): Charles S. Cox; Xin Zhang
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Paper Abstract

The shape of the ocean surface on a millimeter scale controls the scattering of microwave radiation, hence the measurement of oceanic properties by remote sensing. In addition the micro-turbulence immediately adjacent to the sea surface brings about transfers of momentum, soluble gases such as CO2, and heat or water vapor through the lowermost layers of air and the water immediately below. Although these processes are of vital importance to our understanding of the oceans and climate, they have not been adequately studied at sea. Recent developments of optical techniques have greatly simplified measurements of small scale fluid motions and have made them accessible to measurement from a small raft in the open sea. A contributing factor in these developments is the availability of high power, high efficiency visible light diode lasers and high resolution CCD arrays. Optical methods have the advantage that they do not influence the delicate motions of capillary waves at the sea surface, nor are they intrusive in the motions of small turbulent eddies. Our light source for study of turbulence below the water surface is a diode bar laser array. Light generated by the laser array is refracted into a fan shaped light sheet of approximate dimensions 50 by 20 by 2 mm to illuminate particles in the water. Sea water is sufficient transparent to this deep red light that particle tracking and particle image velocimetry can be carried out. The laser and a CCD camera in their water proof containers are so compact that they do not materially interfere with the water flow despite being mounted below the sea surface.

Paper Details

Date Published: 21 November 1997
PDF: 8 pages
Proc. SPIE 3172, Optical Technology in Fluid, Thermal, and Combustion Flow III, (21 November 1997); doi: 10.1117/12.279735
Show Author Affiliations
Charles S. Cox, Scripps Institution of Oceanography (United States)
Xin Zhang, Scripps Institution of Oceanography (United States)

Published in SPIE Proceedings Vol. 3172:
Optical Technology in Fluid, Thermal, and Combustion Flow III
Soyoung Stephen Cha; James D. Trolinger; Masaaki Kawahashi, Editor(s)

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