Seabed resident event driven profiling system (SREP). Concept, design and tests

The seabed resident event driven profiling system (SREP) described here offers a novel, optimized approach to profiling in coastal waters from seabed to sea surface during the rough seas encountered in the southwest monsoon season (June-Sept). It consists of a winch system and a tethered instrumented profiler. The winch system launches and retrieves the profiler. The tethered profiler is programmed to move up and down the water column to sample and transmit water column properties when it reaches the sea surface. It uses standard oceanographic sensors to measure vertical structure at ~0.25m resolution. The major challenges addressed in this paper are long endurance of three months, underwater acoustic communications between the sea bed and the profiler unit and data transmission by the profiler to the shore.