1. Ship-based observations: CTD, Nansen and Niskin bottles, inverting thermometer and Acoustic Doppler Current Profiler
Ben Lee
December 2, 2005
EPS 131

2. Topics Overview of ocean sampling and measurement
CTD (Conductivity, Temperature, Depth)
Acoustic Doppler Current Profiler
Niskin bottles
Nansen bottles
Inverting or reversing thermometers

3. Measurement and Sampling of the Ocean

4. CTD (Conductivity, Temperature, Depth)

5. Conductivity measurement
Accuracy: 0.75 psu (practical salinity unit)
Ocean water: 35 psu = 35,000 ppm (by weight) of salt in water
Temperature measurement
Thermistor (Pt)
Range: -1 to 40 deg C
Accuracy: +/- 0.1deg C

7. Niskin bottles
Bottles can be closed when desired by researchers on the ship
Water samples can be obtained to calibrate the CTD and to investigate properties not measured by the CTD such as dissolved nutrient content, carbon dioxide, chlorofluorocarbons, and others tracers.

8. Acoustic Doppler Current Profilers
Can be mounted horizontally to sea walls or bridge pilings in rivers
anchored to seafloor
to the bottoms of ships
lowered on a cable from ships
Utilizes the Doppler affect to calculate particle speed in water
Transmits “pings” and records signals that have ricocheted off particles

9. ADCP
Petroleum jelly and chili powder repel barnacles without interrupting sound waves
Garbage bags and electrical tape can keep the rest of the instrument clean
In deep oceans (> 1000 m) two ADCP are lowered together one facing the surface and the other facing the bottom, to double the length of the current profile

10. Nansen bottles
Approximately 12 to 24 Nansen bottles are attached in series at predetermined intervals along a cable
Deployed with both ends open
Closes as the bottles are reversed
Used in conjunction with inverting or reversing thermometers

11. Inverting thermometers
Has a constriction in the capillary that allows it to retain its reading upon being inverted
Deployed in pairs, one protected and the other unprotected from high pressures. Combination of the two gives temperature and pressure at the depth where reversal took place

12. References:
Ocean Explorer, National Oceanic and Atmospheric Administration,
Introduction to Physical Oceanography, Robert H. Stewart,
Oceanic In-Situ Data Access, National Oceanic and Atmospheric Administration,
Ocean World,
Edge of the Arctic Shelf, Woods Hole Oceanographic Institution,
Coastal Ocean Institute and Rinehart Coastal Research Center,
Glossary of Meteorology, American Meteorological Society,

13. Any Questions?