Remote sensing (oceanography)

Remote sensing in oceanography utilizes instruments located at a distance from the ocean surface to gather information about the marine environment. This contrasts with in-situ measurements which are taken directly within the ocean. Remote sensing techniques offer a unique perspective, allowing for large-scale spatial coverage and repeated observations over time, crucial for understanding dynamic ocean processes.

Several methods are employed, each sensing different properties of the ocean:

• Satellite Oceanography: This is the most prevalent type of remote sensing in oceanography. Satellites orbiting Earth carry sensors that measure various aspects of the ocean, including:

  • Sea Surface Temperature (SST): Measured using infrared (IR) sensors. SST is crucial for understanding ocean currents, weather patterns, and climate change.
  • Sea Surface Salinity (SSS): Measured using microwave radiometers. SSS is important for understanding ocean circulation and water mass mixing.
  • Sea Surface Height (SSH): Measured using radar altimeters. SSH variations reveal ocean currents, eddies, and the geoid. This data is crucial for understanding ocean dynamics and predicting sea level changes.
  • Ocean Color: Measured using visible and near-infrared sensors. Ocean color provides information on chlorophyll concentration (phytoplankton abundance), suspended sediments, and dissolved organic matter, providing insights into marine biology and ecosystem health.
  • Sea Ice Concentration and Extent: Measured using microwave sensors. This data is vital for monitoring climate change and shipping safety in polar regions.

• Airborne Remote Sensing: Aircraft equipped with various sensors offer a more localized and targeted approach to ocean observation compared to satellites. This allows for higher spatial resolution and the ability to focus on specific areas of interest. Sensors similar to those used in satellite oceanography are employed, as well as others such as:

  • LiDAR (Light Detection and Ranging): Used to map bathymetry (ocean floor depth) in shallow coastal waters.
  • Hyperspectral Imaging: Provides detailed spectral information, enhancing the ability to identify and quantify different water constituents.

• Acoustic Remote Sensing: This involves the use of sound waves to study the ocean. Techniques like sonar are used to map the ocean floor, detect underwater objects, and study ocean currents and marine life.

Data obtained from remote sensing is processed and analyzed using sophisticated algorithms and models to generate valuable information about ocean dynamics, marine ecosystems, and the impacts of climate change. The spatial and temporal coverage offered by remote sensing makes it an indispensable tool for oceanographic research and monitoring. Integration with in-situ measurements further enhances the accuracy and understanding derived from remote sensing data.