We can determine the Earth's gravity field using altimetry measurements.

Several eyes are fixed on El Niño phenomenon : satellites and in-situ observation instruments are deployed to follow its every "move".

Like the winds and rain, ocean currents also change with season, flowing eastward in summer from the western Arabian Sea to the Bay of Bengal, and westward in winter. Altimetry satellites able us to study these currents and their variations; used in coupled ocean-atmosphere forecasting models, their data could help estimate the next monsoon.

Complementarity of altimetric satellites and in-situ data is one of the keys for a three-dimension modeling of the ocean, and for its forecasting.

One of the major unknowns in modeling climate variations is the estimated CO2 content in the atmosphere and absorption of CO2 by the ocean. Here again, satellite altimetry can help.

Doris ground beacons located on the main tectonic plates measure motion and velocities, which range from a few millimeters to 15 centimeters a year.

Altimetric measurements give clues to quantify the slowing down Earth rotation, both with tidal amplitude and undersea reliefs computation.

These are either Rossby waves, which go from East to West or Kelvin waves which move in the opposite direction. They intensify currents such as the Gulf Stream or the Kuroshio.

Merged altimetric satellites improve spatial and temporal resolution of satellite data.

This month, Aviso is bringing you several images in one with a guided tour of some of the oceanographic "curiosities" of the Mediterranean Sea.

Calibration is a key phase in the early stages of a satellite's life : The satellite-to-surface range, associated corrections, the satellite's orbit, wind speed, and wave heights will thus be verified.

Poseidon-2 improvements : a second frequency (in the C-band) for ionosphere corrections, a better sampling, and digital components have replaced analog circuits wherever possible.