The topAWI Triaxus (towed ocean profiler of the AWI) is a towed system manufactured by MacArtney A/S that serves as a device carrier for various sensors measuring parameters relevant to physical, chemical, and biological oceanography. It performs a saw-tooth flight pattern between a few meters below the surface and up to 350m depth at a vertical speed of 1m/s and it can be towed between 2 and 8 knots (1-4m/s) speed through water.
Depending on the exact parameters chosen, this results in a horizontal resolution of 3km or much better, suitable for the synoptic study of mesoscale and submesocale features. Alternatively, it can stay at a constant water depth or a constant distance from the surface (e.g. underside of sea ice) or bottom. The operation in medium-severity sea ice conditions is planned. It can also be deflected horizontally to fly outside of the ship's wake. The Triaxus acts as a pass-through for the sensors such that each sensor is controlled by a separate laptop on the ship.
The following list shows the sensors currently integrated in the topAWI, but the integration of additional sensors is possible/ongoing:
- Seabird "SBE9Plus" CTD with dual temperature, conductivity, and oxygen sensors as well as chlorophyll fluorescence, transmissivity, PAR, and pH
- Seabird "Deep SUNA" nitrate sensor
- 2 Teledyne 1200kHz "Workhorse II" ADCPs (upward- and downward-looking)
- WETLabs "AC-S" Spectrophotometer
- TriOS "RAMSES SAM" Hyperspectrometer
- Simrad "EK80" scientific echo sounder
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