Navis BGC Autonomous Profiling Float
with Biogeochemical Sensors 

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SUMMARY

• Navis Autonomous Profiling Float
• SBE 63 Optical Dissolved Oxygen sensor
• WET Labs ECO Triplet fluorometer / backscattering sensor
• SBE 41CP CTD; same CTD family as used on current Argo floats
• Sufficient power for 250 profile cycles to 2000 dbars
• 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 bolt-on WET Labs ECO Triplet 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 41CP 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 ECO Triplet is three sensors in one, providing any combination of fluorescence (chlorophyll, CDOM, phycoerythrin, phycocyanin, rhodamine, or uranine) and backscattering (blue, green, or red) measurements. The Triplet is clamped to the float hull, and cabled to the end cap.

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.

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 a 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)

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

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 a 2000-dbar profile cycle

Power endurance: 250 2000-dbar cycles

Memory: CTD stores one 2000 decibar 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
• 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
• WET Labs ECO Triplet fluorometer / backscattering sensor
• Navis Profiling Float
• Navis BGCi Profiling Float with Integrated Biogeochemical Sensors

Specifications are subject to change without notice.

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