Comparison of soil moisture fields estimated by catchment modelling and remote sensing: a case study in South Africa
- 1Civil Engineering Programme, University of KwaZulu-Natal, Durban 4041, South Africa
- 2Institute of Photogrammetry and Remote Sensing, Vienna University of Technology, Austria
- *now at: Laboratoire d'étude des Transferts en Hydrologie et Environnement (UMR 5564), 38000 Grenoble, France
Abstract. The paper compares two independent approaches to estimate soil moisture at the regional scale over a 4625 km2 catchment (Liebenbergsvlei, South Africa). The first estimate is derived from a physically-based hydrological model (TOPKAPI). The second estimate is derived from the scatterometer on board the European Remote Sensing satellite (ERS). Results show a good correspondence between the modelled and remotely sensed soil moisture, particularly with respect to the soil moisture dynamic, illustrated over two selected seasons of 8 months, yielding regression R2 coefficients lying between 0.68 and 0.92. Such a close similarity between these two different, independent approaches is very promising for (i) remote sensing in general (ii) the use of hydrological models to back-calculate and disaggregate the satellite soil moisture estimate and (iii) for hydrological models to assimilate the remotely sensed soil moisture.