Altimetry, 20 years and still growing

Image of the Month - August 2012

This month will see the 20th anniversary of the launch of the Topex/Poseidon mission (on August 10, 1992). If Topex/Poseidon is not the first altimetry mission ever (ERS-1 was launched the year before, and several other satellites proved the concept earlier), its launch marks the beginning of a new era for this technique. From then on, the community using altimetry data grew, the number of uses, applications and results bloomed in a wide number of fields.

Blooming applications

Kinetic Energy on 2005/08/31 in the Antarctic Circumpolar Current

Twenty years ago, the objectives of Topex/Poseidon were physical oceanography at large scale, geoid and climate. However, the "unexpected" uses of altimetry (and/or altimetry and auxiliary data) diversified hugely along the years. Here are a few examples (links to first and last references to the subject in the "Images of the Month") of some of those surprises.

Over other surfaces than ocean proper:

New perspectives on the altimetry data were found by researchers (extracted from the radar echoes, from backscatter, etc.)

Mixing data from altimeters and onboard radiometers brought some interesting perspectives:

And, last but not least, over ocean using the "classical" altimetry data, unplanned applications arose:

Also, now, studies and end-user applications mix several techniques: altimetry and other satellite sensors (Sea Surface Temperature, ocean color or Synthetic aperture Radar, etc.) , altimetry and in situ (Argo, etc.), altimetry and models...

A growing community

1988 and 2010 Science Team meetings

At the very beginning of Topex/Poseidon, the community of users consisted mostly in the 35 Principal Investigators (and their teams) of the Science Working Team. Now, the Ocean Surface Topography Science Team itself is about 85 PIs, and the annual meetings include about 200 persons. Next meeting will include even more engineers, researchers and scientists (more than 400), since, to celebrate the 20 years of altimetry, a general altimetry meeting will be held end of September, in Venice.

110 Aviso users were registered by 1993 (Aviso Newsletter #2, May 1993) ; now there are more than 3200, and this including "only" direct users registered to Aviso. Other data centers do distribute altimetry data. Moreover, altimetry is in fact useful for a much larger number of persons, e.g. through ocean models outputs, since those assimilate altimetry data routinely.