Navis BGCi Autonomous Profiling Float
with Integrated Biogeochemical Sensors 

Print version          Compare features across Navis product line          View data from Navis BGC floats

SUMMARY

• Navis Autonomous Profiling Float
• SBE 63 Optical Dissolved Oxygen sensor
• WET Labs MCOMS fluorometer / backscattering sensor
• Multiple optional bolt-on sensors
• SBE 41N CTD -- integrated data stream for all sensors on float, and continuous profiling from 2000 dbar; same CTD family as current Argo floats
• Sufficient power for 250 profile cycles to 2000 dbars (excluding optional bolt-on sensors)
• Flexible mission sequencing, allowing for more frequent sampling in upper water column
• Backed by Sea-Bird Scientific warranty

DESCRIPTION

A Navis autonomous profiling float with integrated optical Dissolved Oxygen sensor (SBE 63) and WET Labs MCOMS is now available from Sea-Bird Scientific. The sensors take continuous measurements at 1 Hz through ascent, and provide high accuracy, resolution, and stability.

• The SBE 41N CTD measures conductivity, temperature, and pressure (depth). The pump-controlled, T-C ducted flow minimizes salinity spiking caused by mismatch of temperature and conductivity measurements.
• The individually calibrated SBE 63 Optical Dissolved Oxygen sensor is integrated within the CTD flow path, providing optimum correlation with CTD measurements.
• The MCOMS is three optical sensors in one, providing chlorophyll a, backscattering, and CDOM. The MCOMS is integrated directly into the float end cap and co-located with DO and physical measurements.

The carefully engineered anti-foul protection includes anti-foulant devices, a U-shaped flow path, and an integral pump. On the float’s ascent, as it approaches 10 to 5 dbars beneath the ocean surface, the pump turns off. The U-shaped flow path prevents sea surface oils and contaminants from being ingested while proceeding through the ocean surface skin and sitting at the surface during data transmittal. Between profiles the pump is off. The U-shaped flow path prevents water flow through the system caused by waves or currents; minute amounts of anti-foulant concentrate inside the conductivity cell to minimize bio-fouling.

As an option, multiple sensors can be attached to the float hull and cabled to the end cap. Data from all sensors, including the optional bolt-on sensors, is integrated in the data stream by the SBE 41N CTD electronics. Currently available bolt-on sensors include the Satlantic Deep SUNA (nitrate), Satlantic OCR 504 (4-channel radiometer), and WET Labs C-Rover 2000 (transmissometer); check this datasheet for updates.

For detailed information on the operation of the Navis float, see the Navis float datasheet.

Navis BGC Float Deployment in the Mediterranean (photo by Christoph Gerigk © Sea-Bird Electronics)

SPECIFICATIONS

Measurements:

• Temperature: ± 0.002 ºC initial accuracy, 0.0002 ºC/year stability
• Salinity: ± 0.002 PSS-78 initial accuracy, 0.001 PSS-78/year stability
• Pressure: ± 2 decibars initial accuracy, 0.8 decibars/year stability
• Dissolved Oxygen: ± 3 µmol/kg or 2% initial accuracy, <1 µmol/kg/100,000 samples stability (20 ºC; sample-based drift)
• Chlorophyll Fluorescence: ± 0.2% of full scale initial accuracy (relative to specific monoculture of phytoplankton [diatom] grown in specific light/nutrient conditions)
• CDOM Fluorescence: ± 0.3% of full scale initial accuracy (relative to Quinine sulfate dihydrate)
• Backscattering: ± 0.2% of full scale initial accuracy (relative to polystyrene beads [2 µm ± 0.1 µm mean diameter])

Volume change: 1.7% (minimum fractional)

Depth rating: 2000 decibars

Communications: Iridium Transceiver 9523 -- RUDICS, circuit switched. Nominal transmission time 275 sec for 2000 dbar profile cycle (2 dbar bins of 1 Hz data; excluding optional bolt-on sensors)

Position: GPS, Garmin 15xL-W, mean acquisition time 20 sec

Park interval: 1 - 15 days

Materials: Aluminum hull, seamless natural rubber external bladders

Oil reservoir: 300 ml

Ballasting: Self-ballasting, 1 day to equilibrate

Weight in air: Less than 20 kg (excluding optional bolt-on sensors)

Box: Stackable, export-compliant

Self-activation: Starts operating automatically on deployment, when pressure reaches user-programmable setpoint

Internal batteries: 4 packs of 3 DD lithium sulfuryl chloride cells (cannot ship in passenger aircraft; Class 9 Dangerous Goods). Each pack has 10.8 V open circuit voltage & 30 AH capacity; 1166 kJ (4664 kJ/4 packs).

Power consumption: 13 kJ for 2000-dbar profile cycle (excluding optional bolt-on sensors)

Power endurance: 250 2000-dbar cycles (excluding optional bolt-on sensors)

Memory: CTD stores one 2000 dbar profile

Dimensions: Hull diameter 14 cm (5.5 inches), Ring diameter 24 cm (9.5 inches), Total length 167 cm (65.7 inches)

ADDITIONAL INFORMATION / LINKS:

Documentation -- manual, photos, technical papers, application notes, etc.

• Print version of this specification sheet / brochure
• View data from Navis BGC floats
• New Generation of Instrumentation for Navis Profiling Floats, poster presentation, 2014 Ocean Sciences
• Biogeochemical Monitoring of the Oceans Using Autonomous Profiling Floats, Ocean News & Technology, Volume 19, Issue 2, March 2013
• Presentation from March 2013 Argo Steering Team meeting
• Navis Float Product Guide -- selection guide for the best float for your application

Links to Other Products of Interest

• SBE 41 / 41CP Argo CTD
• SBE 63 Optical Dissolved Oxygen sensor
• Navis Profiling Float
• Navis BGC Profiling Float with Biogeochemical Sensors (bolt-on)

Specifications are subject to change without notice.

Sea-Bird Home     Phone: (+1) 425-643-9866     E-mail: seabird@seabird.com