Monitoring water levels in the Pantanal floodplain using satellite altimetry data

Satellite altimetry was developed and optimised for studying sea level variations over open oceans. Its use for monitoring level variations of inland waters such as lakes, rivers and floodplains have demonstrated great potentialities yet. In this study we focus our attention on the Pantanal floodplain (La Plata basin). Our goal is to identify possible signatures of climate variability on water levels. First, time series of the Pantanal floodplain water levels are derived from altimeter data of the Topex/Poseidon satellite over the period 1993-2002 for different sites. The data used are the 10 Hz, which corresponds to along-track ground spacing of 580 meters. Second, we analyse both spatial and temporal variability in water levels by applying an Empirical Orthogonal Function (EOF) analysis for the selected sites after removal of the average seasonal cycle. The water level time series over the Pantanal floodplain are further compared to results obtained earlier with Topex/Poseidon altimetry over the Parana, Paraguay and Uruguay rivers. These satellite-derived observations are interpreted in terms of hydrologic and climate variability over the La Plata basin.