Shipboard nowcasting of shelf circulation

A system has been developed which provides up-to-the-hour hindcasts and short term forecasts for the flow within the domain of a regional hydrodynamic model. The enabling technology is outlined here and principally includes: (i) a ship-board anemometer and Acoustic Doppler Current Profiler; (ii) telemetry systems for current meter moorings and LORAN-C drifters; (iii) an ethernet-linked network of PCs and workstations running data processing software; and (iv) an assimilative regional hydrodynamic model. The first operational application of the system has recently been completed on the outer Scotian Shelf where fisheries biologists needed to track a cohort of cod larvae (Gadus morhua) for 2–3 weeks. The cruise was successful: a patch of larvae initially 20 km across was found and tracked for 19 days despite the cruise being interrupted halfway through by storm force winds which forced the ship back to port for several days. Selected examples of data acquired on the cruise are presented to illustrate the usefulness of the system.