Détails Publication
Comparison of methods to derive the height-area relationship of shallow lakes in west africa using remote sensing,
Discipline: Sciences de la Terre
Auteur(s): F. Girard, L. Kergoat, E. Nikiema, M. Wubda, R. Yonaba, T. Fowé, A. Abdourhamane Touré, I. Mainassara, M. de Fleury, M. Grippa
Auteur(s) tagués: NIKIEMA Dayangnewende Edwige
Renseignée par : WUBDA Maxime
Résumé

In West Africa, lakes and reservoirs play a vital role as they are critical resources for drinkingwater, livestock, irrigation, and fisheries. Given the scarcity of in‐situ data, satellite remote sensing is animportant tool for monitoring lake volume changes in this region. Several methods have been developed to dothis using water height‐area‐volume relationships, but few publications have compared their performances oversmall and medium‐sized shallow lakes. In this work we compare four methods based on recent data from high‐resolution optical imagery and radar and lidar altimetry over 16 lakes in the Central Sahel, with areas between0.22 km2 and 21 km2. All methods show consistent results and are generally in good agreement with in‐situ datain terms of accuracy (Root Mean Squared Error below 0.42 m for heights and Normalized Root Mean SquaredError below 13% for volumes). The precision of the estimated water height is about 0.20 m for Pleiades DigitalSurface Models (DSMs) and less than 0.13 m for the other methods. Inherent limitations such as DSM quality, temporal coverage of DSM and lidar data, and spatial coverage of radar altimetry data are identified. Overall,fine shape patterns are consistently observed over small height amplitudes, highlighting the ability to monitorshallow lakes with non‐linear height‐area relationship. Finally, we show that combining lidar and radaraltimetry‐based methods provides estimates of volume changes over the different water bodies of the studyregion accurate enough to monitor seasonal, interannual, and long‐term variability.

Mots-clés

Height-erea-volume, Radar and lidar altimetry, Inherent limits, spatio-temporal coverage

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