GLERL 2004 Milestone Reports

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GOAL: Protect, Restore and Manage Use of Ocean and Coastal Resources Through Ecosystem Management Approaches

Scientist: Dr. Michael McCormick (GLERL)

NOAA Performance Measure: Increased area covered and number of ecological conditions monitored by stat-of-the-art observation systems and platforms that provide necessary information about NOAA’s stewardship responsibilities.

OAR Performance Measure: Provide evaluation of the utility of RAFOS drifting buoys for application in the Great Lakes. Baseline 0, Target 1 deployment

Milestone: Investigate the utility of PAFOS underwater drifting buoy on Lake Champlain to describe subsurface water transport.

Purpose: To determine if RAFOS buoys, specifically designed for a freshwater environment, are capable of resolving the below thermocline circulation in a large lake.

Efforts and Results (to date): After two years of mechanical difficulties SeaScan, Inc. built several successful RAFOS buoys suitable for freshwater applications. In 2003 six different sound sources were strategically placed in Lake Champlain. The sound sources transmitted at 1560 Hz with an hourly transmit time staggered at ten-minute time intervals. A RAFOS buoy was released in July 2003 and remained at 30 m depth for seven days when it was retrieved at the surface. Evaluation of the onboard RAFOS data showed excellent buoyancy control and recognition of the different sound sources enabling accurate position fixes. The buoy showed a net mean velocity to the north of 0.4 cm/s with associated decorrelation time and space scales of 13.7 h and 1 Km. This technology shows great promise to possible future Great Lakes applications although its relatively high cost may be an obstacle.

Customer(s): General scientific community and water resource managers

Cause Factors (if milestone not met): N/A

Revised Completion Date (if milestone not met): N/A

Last updated: 2004-09-23 js