U.S. GLOBEC: Phase II Retention Processes- Moorings and Highly Resolved Hydrography

K.H. Brink, C.M. Lee

The objective of our work is to make quantitative, process-oriented estimates of the offshore fluxes of water and biota from the southern side of Georges Bank. We are particularly interested in the fluxes associated with warm-core ring encounters, wind-driven (Ekman) transport and shelf break eddies (instabilitites).

Our sampling will make use of SeaSoar, a towed, undulating vehicle. Typically, it can be towed at about 8 knots, cycling between 5 and 120 m depth with periods of about 10 minutes or less. This platform will be equipped with a video plankton recorder (VPR: Davis and Gallagher), a TAPS (acoustic zooplankton sampler: Holliday and Berman),a fluorometer, a transmissometer, a PAR (photosynthetically Available Radiation) sensor, as well as more standard measurements (conductivity, temperature and pressure). In addition, shipboard ADCP current measurements will be made throughout. The proposed SeaSoar configuration, involving the VPR, is new, so that a significant engineering will be involved for adapting the system.

The seagoing work calls for three cruises. First, In November 1996, there will be a six day engineering cruise to test the new SeaSoar configuration and to make any needed adjustments. Next come two process cruises (March and June 1997), each of 11 days duration. Both of these cruises should allow about 5 two-day highly resolved SeaSoar surveys. Analysis extends through the second and third years of funding.

Some changes from the original proposal were made to reach budget targets. Overall personnel time went down, and Lee took over a good deal of responsibility from Brink, whose role has been considerably lessened. Also, one science cruise, originally planned for July 1997 was deleted, while a May cruise was changed to June. Detailed cruise times have yet to be resolved.