Remote Sensing is gathering information about something without being in physical contact with it. Information derived from satellites about the ocean, like sea surface temperature and chlorophyll and many marine geoscience techniques are considered to be remote sensing.

Oceanographic Remote Sensing includes sea surface temperature (SST), sea colour, including chlorophyll and satellite altimetry, which measures the height of the ocean.

Geoscientific Remote Sensing techniques include multibeam swath bathymetry, seismic surveys and sidescan sonar.

Satellite remote sensing generally relies on cloud-free days, as clouds block the electromagnetic radiation (visible light and infra-red) needed to calculate sea surface temperature and ocean colour/chlorophyll. If you see black areas in the remote sensing images on this site such as those below, these generally show you where cloud cover was obscuring the surface so no measurement could be taken.

The ability of remotely-sensed sea surface imagery to gather data over large areas simultaneously over long time periods and at relatively low ongoing cost is invaluable in understanging those oceanographic phenomena which interact with the surface, and has lead to considerable advances in our understanding of the oceans.

Ocean colour allows us to extrapolate the amount of chlorophyll in the water, which is a good proxy for the primary production (phytoplankton, microscopic marine plants) of large areas of ocean.

Both of these two measurements can only record the state of the surface of the sea; deeper than this we rely on in situ  observations; cruises aboard well equipped research vessels will likely form a vital cornerstone of oceanography for a long time to come. Such cruises also provide us with the opportunity to "ground truth" the data inferred from remote sensing techniques, which can sometime be incorrect, and allows further corrections to the formulae that calculate such data from satellite imagery.

Satellites are also able to tell us in detail about the height of the sea; this allows us to detect phenomena such as eddies, which cause a deviation ("anomaly") from the mean (average) sea surface.

Up-to-date remote sensing images and a long term archive of historical data and imagery of regional interest can be found on the remote sensing server, an initiative of a number of partners including ACEP.