Exploration of the potential of RADAR products for spatio-temporal characterization of the hydroperiod in the Palo Verde wetlands in Costa Rica

Details

Supervisors

Javaux, Mathieu ; Alonso, Alice

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences et technologies de l'environnement, à finalité spécialisée

Abstract

The Palo Verde wetland, located in the Tempisque-Bebedero watershed in northwestern Costa Rica, is a Ramsar site important for its rich biodiversity. This master thesis aims to understand how radar data can enhance knowledge of the hydrology of this area, which is particularly vulnerable to anthropogenic changes. The study explores two main aspects: the use of the backscatter coefficient to estimate the entire flooded areas, and the analysis of water level variations using radar interferometry (InSAR). The results show that the L-HH backscatter coefficient, combined with vegetation indices, allows for the identification of flooded vegetation areas. A classification of the wetlands was performed and achieved an accuracy of 94% for the wet season and 83% for the dry season through machine learning classification techniques. However, the lack of reliable ground data limited the calibration of radar observations, complicating the interpretation of SAR images. The InSAR analysis revealed challenges related to image coherence in this complex environment. Despite these limitations, the study demonstrates the potential of radar products to better understand the hydrological dynamics of the Palo Verde wetlands. These findings lay the groundwork for future research aimed at improving ground data collection and radar processing techniques for more effective management of this ecosystem.