PhD in Remote Sensing, Remote Sensing Physics program


Kalifa Goita et Ramata Magagi

Field of research

Characterization of the hydrological regime of water bodies subjected to freezing and thawing from multi-satellite altimetry data

Monitoring hydrological systems subject to ice action, as in Canada, requires the availability of a hydrometric measurement network capable of providing estimates at a given location and over a given time period. The use of satellite altimetry responds to this problem thanks to its advantages related to its spatial and temporal resolution and the use of reprocessing algorithms. These algorithms have the potential to detect anomalies on altimeter waveforms, which provides hydrological magnitudes that are the water levels of lakes and rivers.

However, the presence of ice within the altimeter footprint leads to heterogeneity in altimeter waveforms. This could reduce the functioning of the reprocessing algorithms and the quality of the estimates obtained.

This hypothesis will be studied on the basis of a comparative analysis between time series of water levels derived from existing reprocessing algorithms as a function of the evolution of the ice regime. In this project, this comparative analysis will allow us to define the degree of power of each algorithm as well as the periods from which water level estimates become inaccurate.

The hypothesis of discrimination between the ice fraction and open water within the altimeter footprint will improve hydrological estimates in the presence of ice cover. To do this, this project will use demixing techniques to define the pure element proportions composing the waveforms of the mixture (water-ice). This decomposition will lead us to develop an inversion algorithm capable of providing good altimetric estimates in the presence of ice.


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