The Amazon under close surveillance

Image of the month - October 2001

Topex/Poseidon ground tracks over the Amazon's basin. Yellow and red dots show where the altimeter radar beam is well reflected. Yellow-framed zones: left, Amazon system upper part (Solimoes river), near the Peru/Brazil border; right the beginning of Amazon itself, at the meeting point between Negro and Solimoes rivers, near the city of Manaus (Brazil). (Credits Legos).
Water level variations on the upper part of the Amazon (over the Solimoes river), in the two regions marked above. Topex/Poseidon measures annual variations of about 8 meters. (Credits Legos)

The Amazon is the world's largest river system, but it is poorly understood because few in-situ measurements from its remote regions are available. This river is in many places large enough to reflect well the radar wave from the altimeter. Thus altimetry satellites are now being used to monitor its water level variations, permanent and temporary flood zones, and various other parameters, fro a better water and natural hazard management in this region.

More and more satellite altimetry is being used over other surfaces than ocean and sea like lakes, rivers and even flat surfaces (deserts...). For this, special processing must be done, in order to take acount of the different ways the radar beam can be reflected.

See also:

  • Applications: Hydrology and land

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