Caractérisation de la qualité du niveau des cours d'eau mesurés par altimétrie satellitaire radar : premiers pas pour une méthode standardisée

[Departement_IRSTEA]DS [TR1_IRSTEA]METHODO / SYNERGIEThe potential contribution of satellite radar altimetry to the monitoring of inland water levels (inner seas, lakes, floodplains and large rivers) has been demonstrated by numerous works during the last 15 years. Currently a significant number of satellites provide radar altimetry information and could ensure the continuity of operational monitoring of continental water levels. Still, hydrologists do not use these data for operational applications such as water resource quantification, flood forecast or water resource management. Among the reasons accounting for hydrologists reluctance to use water level data derived from satellite radar altimetry is the lack of a standardized method to characterize the quality of these data [Birkett1998]. This paper focuses on that subject and proposes a standardized methodology for two complemetary purposes (1) the quantification of the accuracy and uncertainty of individual satellite measurements, (2) the characterization of the quality of daily water level time series reconstructed from sampled satellite radar altimetry measurements. This method will both (1) contribute to provide to hydrologists radar altimetry water level time series with associated uncertainty, thus allowing hydrologists to use qualified data, (2) allow the quantification of improvements generated by new processing chains (waveform retracking algorithms, filtering techniques, interpolation techniques, etc.)