1. GEOL 1033 (Lesson 26) Ppt file 103-22
PHYSICAL OCEANOGRAPHY. Part 1: Introduction, Measurements, Instruments, etc.
GEOL 1033
(Lesson 26)
Ppt file

2. PHYSICAL OCEANOGRAPHERS
Interested in
Heat exchange
Evaporation
Density
Temperature
Water movements: currents, waves, tides, etc.
Other physical properties of water
Measures:
Salinity
Oxygen content
Pressure
Currents

3. Some Physical Oceanography Instruments
Nansen bottle
For water sample collection
Lowered on a cable
Activate with a “messenger” (= a little weight that slides down the cable until it hits and triggers the bottle to take a sample.)

4. Some Physical Oceanography Instruments
Nansen bottle Collecting water samples at some depth

5. Some Physical Oceanography Instruments
Bathythermograph
BT = acronym
Usually lowered on a cable
Sensitive to
Temperature and
Water pressure, which is related to depth
Measures any changes in temperature as depth increases
XBT = acronym for “expendable” bathythermograph
Dropped from
a moving boat or
even from an airplane
Radio sends data back to ship/plane

6. Some Physical Oceanography Instruments
BT (bathythermograph)
Graphic profile of temperature variation with depth inscribed on a black-coated glass slide

7. Some Physical Oceanography Instruments
XBT =
Expendable BT
Can be attached by a cable to a recorder on ship
Depth can be calculated because of known rate of descent.
Data is radioed back to an airplane that drops one

8. Some Physical Oceanography Instruments
STD device
Electronic
Lowered on a cable
Measures while being raised or lowered:
Salinity
Temperature
Depth (by measuring associated pressure changes)
Transmits data by cable back up to ship

9. Some Physical Oceanography Instruments
Rosette, a STD device:
Collect many water samples
Up to 10 x30 L Nansen bottles
Can be triggered electronically
Pinger used to locate depth (or depth can be determined by pressure changes)
Can record other information at the same time:
suspended particle matter
oxygen

10. MEASURING CURRENTS

11. MEASURING CURRENTS Current meters Mechanical Induction
A fan-like device (rotor) spins on a shaft of a generator
Electrical output is calibrated to water speed
Induction
Applies the principle that salt water is a conductor, so as water flows through a coil of wire an electric current is generated that can be calibrated.

12. MEASURING CURRENTS Indirect methods of studying water currents:
Measure other water properties whose variations indicate water movements
Study:
Oxygen content
Temperature
Salinity
Density
Radioactive isotopes, e. g., 90Sr
Distribution of warm- or cold- water organisms (Gulf Stream example)
Imagery
Airplane = Aerial photographs, e. g., visible spectrum, infrared, etc.
Satellite = infrared, reflectivity, visible-light, radar, etc.

13. MEASURING CURRENTS
Determining coastal surface ocean current systems using aerial photography

14. Satellite Remote Sensing of the Grand Banks
Renewed petroleum exploration in the 1980's inspired greater oceanographic research
370 km Canadian exclusive fishing zone

15. SATELLITE IMAGERY TO MEASURE SURFACE TEMPERATURES

16. SATELLITE IMAGERY TO MEASURE SURFACE TEMPERATURES
Calibrations permit mapping surface temperature variations

17. END OF FILE