Technology

Applications

• Maritime Weather Monitoring and Prediction
• Navigational Improvements
• Hydrography
• Fisheries -- Food from the Sea
• Coastal Engineering
• Coastal Hydrology
• Sea Ice Prediction and Tracking
• Data Transmission

Devices

I. Platforms

• Fixed Platforms
  • Consist of towers and platforms fixed on the ocean floor
  • Used to acquire long-term measurements in locations where mobile platforms would be impractical
• Floating Platforms
  • First method used to apply remote sensing to oceanography
  • Consists of ships and buoys with cameras and IR radiation thermometers to study surface characteristics.
  • Early data collected consisted of the air-sea exchange across the surface.
• Balloons
  • Used in most ocean operations.
  • Cheap, compact, reliable way allowing measuring from above the ocean surface.
  • Responsible for finding archaeological sites shallow waters. How? By observing anomalous patterns against the sea floor from balloons towed by research vessels.
  • Moored balloons are often used to provide measurements over periods.
• Airships (blimps)
  • As a measurement device, when useful for low speed, endurance, and good payload capability are wanted.
  • Few are used due to low quantity in existence.
• Aircraft
  • Most common device used to apply remote sensing to measurement of oceanographic aspects.
  • Used for aerial survey, sensors test for spacecraft platforms.
• Spacecraft
  • Provide rapid coverage of an area on a real-time basis.
  • During the 1960's, unmanned weather satellites were not specifically used to produce oceanographic data but much of the data collected has been used in studies of the oceans.
  • During the 1970's, manned and unmanned earth-orbiting satellites collected data concerning overall pollution of the plant.
  • The future includes specific ocean-oriented sensors in orbit.

II. Sensors

• Passive Sensors
  • Ultraviolet Band
    • Not commonly used.
    • Usually combined with UV (ultraviolet) with visual and IR (infrared) bands.
  • Visible Band
    • Largest class of imagery.
    • Primarily used by cameras and photographic emulsions.
  • Infrared Spectrum
    • Measures heat fluxes above, at, and beneath the sea-air surface.
    • Used by imager (produces imagery mapping of the ocean surface with thermal contours) and radiometer-spectrometers (provides values of apparent temperature of the surface at points across the ocean).
  • Microwave Spectrum
    • Used to measures temperature, surface brightness (index to wind and wave action), and salinity (relationship of salt-to-water content) of the ocean,
    • Not affected by high altitudes or poor weather.
• Active Sensors
  • Lasers
    • Can collect accurate altitude information for geophysical measurements such as the slope of the ocean surface, and wave height measurements.
    • Also, can be used to identify materials, such as oils and sediments, at the sea surface.
  • Radars
    • Used to measure phenomena, such as coastal features, river outflows, surface boundaries, fish schooling, and waves.
    • Can be used during all types of weather (at which passive sensors would be rendered ineffective).