InSAR monitoring of ground motions impacts for in-situ sea level measurement: The example of Dakar (Senegal)

Gonéri Le Cozannet (1, 2) , Daniel Raucoules (1) , Guy Woppelmann (3) , Marcello de Michele (1) , Adrien Poupardin (4)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
2 LGP - Laboratoire de géographie physique : Environnements Quaternaires et Actuels
3 LIENSs - LIttoral ENvironnement et Sociétés
4 LOMC - Laboratoire Ondes et Milieux Complexes

Tide gauges are a unique source of information on past sea level changes over the 20th century. However, these instruments can be affected by local ground motions, which are often poorly known. Here, InSAR can provide valuable information to understand the ground deformation context at city scale. In this study, we evaluate ground motion velocities from 13 interferograms of 10 Envisat images. Within the precision limitations of the technique, our results suggest that the city of Dakar displays relatively uniform ground motions, except in the harbor. Further investigation is necessary to examine the particular case of a recent tide gauge, which could be affected by a moderate subsidence with respect to the permanent GPS station of Dakar.

Mots clés: Cities and towns; Global Positioning System; Sea level; Sea measurements; Tides; Dakar; InSAR; Sea level rise; Tide Gauge; ground motions

Domaines: Sciences de la Terre

Gonéri Le Cozannet, Daniel Raucoules, Guy Woppelmann, Marcello de Michele, Adrien Poupardin. InSAR monitoring of ground motions impacts for in-situ sea level measurement: The example of Dakar (Senegal). IEEE. Geoscience and Remote Sensing Symposium (IGARSS), 2014 IEEE International, Jul 2014, Quebec City, QC, Canada. pp.970-973, 2014, Geoscience and Remote Sensing Symposium (IGARSS), 2014 IEEE International, ⟨10.1109/IGARSS.2014.6946588⟩. ⟨hal-01082293⟩