Geodesy and Geophysics

SENTINEL-3 Altimetry Geodesy and Geophysics

The Sentinel-3 topography mission could be useful for the study of the Earth's shape and size, gravitational anomalies or sea floor relief.


Satellite altimeter measurements, in combination with sparse measurements of sea floor depth, can be used to construct a uniform resolution map of the sea floor topography. These maps do not have sufficient accuracy and resolution to be used to assess navigational hazards but are useful for diverse applications such as locating obstructions or constrictions to the major ocean currents, and locating shallow seamounts where sea life is abundant.


Geodesy is the science of the Earth's shape and size. Altimetry makes it possible to compute Mean Sea Surface. Such a surface includes the geoid, i.e. the shape of the sea surface, assuming a complete absence of any perturbing forces (e.g. tides, winds, currents). The geoid reflects the Earth's gravitational field. It varies in height by as much as 100 m over distances of several thousand kilometres due to uneven mass distribution within the planet's crust, mantle and core. Other less pronounced irregularities are also visible over smaller distances. These mostly reflect the bathymetry (ocean bottom topography).

Figure 1: Geophysical Information Extracted from Altimetry (Credit: University of Calgary)

For further information about applications related to geodesy and geophysics see: Radar Altimetry Tutorial by ESA/CNES.

For further information about land applications and services available, see: Copernicus website.

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