SeaCycler: A Moored Open-Ocean Profiling System for the Upper Ocean in Extended Self-Contained Deployments

Abstract

The upper ocean, including the biologically productive euphotic zone and the mixed layer, has great relevance for studies of physical, biogeochemical, and ecosystem processes and their interaction. Observing this layer with a continuous presence, sampling many of the relevant variables, and with sufficient vertical resolution, has remained a challenge. Here a system is presented that can be deployed on the top of deep-ocean moorings, with a drive mechanism at depths of 150-200 m, which mechanically winches a large sensor float and smaller communications float tethered above it to the surface and back down again, typically twice per day for periods up to 1 year. The sensor float can carry several sizeable sensors, and it has enough buoyancy to reach the near surface and for the communications float to pierce the surface even in the presence of strong currents. The system can survive mooring blowover to 1000-m depth. The battery-powered design is made possible by using a balanced energy-conserving principle. Reliability is enhanced with a drive assembly that employs a single rotating part that has no slip rings or rotating seals. The profiling bodies can break the surface to sample the near-surface layer and to establish satellite communication for data relay or reception of new commands. An inductive pass-through mode allows communication with other mooring components throughout the water column beneath the system. A number of successful demonstration deployments have been completed.

Glider-Based Observations of CO<sub>2</sub> in the Labrador Sea

“…In the fall 2016, a moored vertical profiler, the SeaCycler (Send et al, 2013;Atamanchuk et al, 2020) and a G2 Slocum glider were deployed into the central Labrador Sea near the longtime German deep convection mooring K1 (Figure 1). The K1 mooring, located about 25 km west of former OWS BRAVO (Avsic et al, 2006), has been deployed biennially since 1994 to 3 https://doi.org/10.5194/os-2020-52 Preprint.…”

“…Many observing efforts came together, utilizing multiple complementary efforts across different scientific programs, relying on both traditional and novel observational approaches. Send et al (2013). It has an underwater winch assembly, parked at 160 m depth with an instrument float that can profile the top 150 m. A tethered communication allows for two-way telemetry over Iridium Satellite.…”

“…In 2016, as part of the Ventilations, Interactions and Transports Across the Labrador Sea (VITALS) project, we devised an observing strategy to carry out novel in-situ observations to: (1) Reach the deep convection region with a glider to carry out sampling with the novel foil-based pCO 2 sensor from Aanderaa with minimal ship resources for launch and recovery. (2) Use measurements provided by an autonomous moored profiler -the SeaCycler (Send et al, 2013), carrying the larger payload CO 2 -Pro CV instrument for glider in-situ calibration points. This mission attempted to use a moored sensing platform as an in-situ reference point for experimental sensors deployed on a glider to advance data quality and coherence of novel biogeochemical measurements.…”

100 Years of Progress in Ocean Observing Systems

“…The Moored Profiler (Doherty et al 1999), as an example, employs a traction drive to crawl repeatedly up and down a conventional mooring wire. Other profilers use buoyancy changes to ascend and descend (e.g., Eriksen et al 1982;Provost and du Chaffaut 1996) or combine a buoyant instrument package that floats up and a winch mounted on top of a subsurface mooring to haul it back down (e.g., Barnard et al 2010;Send et al 2013). Other sensor carriers attach to the mooring below a surface float and use a ratcheting drive to tap heave from surface waves to crawl down the mooring line and then release from the line, float up, and lock back on to repeat the sequence (e.g., Fowler et al 1997;Pinkel et al 2011).…”

Timed Communication Buoy System: A Subsurface Mooring System for Efficient Sensor Data Recovery

“…Send et al (2012) developed a winch-driven profiling float system based on the subsurface mooring system called SeaCycler. The whole system included a sensor float, a communication float, and a mechanism float.…”