Temporal variations of river basin waters from Topex/Poseidon satellite altimetry. Application to the Amazon basin

Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science, Volume 333, Issue 10, 30 November 2001, Pages 633-643
Ilce de Oliveira Campos, Franck Mercier, Caroline Maheu, Gérard Cochonneau, Pascal Kosuth, Denizar Blitzkow and Anny Cazenave



Summary of Points:

·        Although developed and optimised for open oceans, satellite altimetry has the potential to monitor level variations of inland surface waters such as lakes and rivers. The article presented results of water level variations of the Amazon river based on eight years (1993¯2000) of altimetry data of the Topex/Poseidon satellite.

·        The dominant signal is seasonal, mostly annual, with an amplitude of up to 10¯15 m peak to peak. Comparison with in situ measurements indicates that water levels are well measured by Topex/Poseidon during high-water season, unlike low-water season, which suffers from data gaps.

·        The article also discusses the interannual component of the signal, which shows two marked minima in 1995 and 1998. The 1998 minimum is interpreted as an effect of the 1997¯1998 ENSO event, causing rainfall deficit in the central part of the Amazon basin, hence decrease in water levels. An EOF analysis of precipitation fields over the basin during the 1993¯1999 period confirms the rainfall minimum by the end of 1997 for this region.

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