HR: 14:40h
AN: OS53B-05    [Abstracts]
TI: Small-scale turbulence measurements with a free-falling DPIV profiler
AU: Steinbuck, J V
EM: vittorio@stanford.edu
AF: Stanford University, Dept. of Civil and Environmental Engineering, Stanford, CA 94309 United States
AU: * Troy, C D
EM: carytroy@stanford.edu
AF: Stanford University, Dept. of Civil and Environmental Engineering, Stanford, CA 94309 United States
AU: Franks, P J
EM: pfranks@ucsd.edu
AF: Scripps Institute of Oceanography, Svedrup Hall, La Jolla, CA 92093 United States
AU: Karakoylu, E
EM: ekarakoy@ucsd.edu
AF: Scripps Institute of Oceanography, Svedrup Hall, La Jolla, CA 92093 United States
AU: Jaffe, J S
EM: jules@mpl.ucsd.edu
AF: Scripps Institute of Oceanography, Svedrup Hall, La Jolla, CA 92093 United States
AU: Jaffe, J S
EM: jules@mpl.ucsd.edu
AF: Scripps Insitution of Oceanography, NTV, La Jolla, CA 92093 United States
AU: Monismith, S G
EM: monismith@stanford.edu
AF: Stanford University, Dept. of Civil and Environmental Engineering, Stanford, CA 94309 United States
AU: Horner, A R
EM: arhorner@stanford.edu
AF: Stanford University, Dept. of Civil and Environmental Engineering, Stanford, CA 94309 United States
AU: Horner, A R
EM: arhorner@stanford.edu
AF: University of Washington, Dept. of Civil Engineering, Seattle, CA 94309 United States
AB: We have recently developed and built a novel free-falling platform with a stereoscopic Digital Particle Image Velocimeter (DPIV) to observe and quantify microscale physical and biological structures in the upper ocean. Scattered light from a vertical sheet of laser illumination is imaged from both sides by sensitive CCD cameras. Sequences of images allow two-dimensional maps of three-component velocity to be constructed from cross-correlations between images. The profiler has the potential to provide direct estimates of turbulent kinetic energy dissipation in the near-surface open ocean. Dissipation rates can be estimated using finite-difference approximations for 8 of the 12 velocity gradient terms. Using a filter wheel in front of the camera lenses, scattered light and two wavelengths of fluoresced light can be imaged sequentially, allowing mapping of fluorescent particles to the turbulent structures in the water column. The spatial and temporal resolution of the system is set by the size of the imaging area (about 20x20 cm with 200 micron resolution), the camera frame rate (8 Hz), and considerations related to the DPIV cross-correlation technique. We discuss some results of preliminary tests both in the lab and at sea.
DE: 4500 OCEANOGRAPHY: PHYSICAL
DE: 4568 Turbulence, diffusion, and mixing processes
DE: 4572 Upper ocean processes
DE: 4594 Instruments and techniques
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting