The use of TerraSAR-X time-series for monitoring the hydric states of slaking crusts in agricultural fields | L'utilisation d'une série temporelle d'images radar TerraSAR-X pour la cartographie de l'état hydrique des croutes de battance en milieu agricole

[Departement_IRSTEA]Territoires [TR1_IRSTEA]SYNERGIE

International audience

English. Through the modification of water-retention properties and infiltration rates, slaking crust structures cause significant environmental problems such as runoff and sheet erosion on agricultural surfaces. Moreover, the state of soil surface structure is one of the most important factors considered in erosion risk assessment. In this paper, we assess the potential of TerraSAR-X time series acquired at very high spatial resolution (1m) to detect the spatial distribution of slaking crust at the within plots scale, and to monitor the dynamics of slaking crust hydric states. We analyzed the behavior of the TerraSAR-X signal for two configurations HH-25° and HH-50°, with regard to several soil moisture content and slaking crust conditions that were recorded during field campaigns in the winter of 2009 and 2010 on the Orgeval watershed (France). For both TerraSAR-X configurations no direct link between the soil crust and the backscattered signal was observed. Nevertheless, TerraSAR-X signal variations within plots were found to be correlated to the hydric evolution of the soil crust. In fact, soil moisture may differ between two soil structures, resulting in variations in the TerraSAR-X signal. All within plot difference of soil moisture greater than 3% could be detected and tracked. Furthermore it is possible to track surface degradation due to the slaking process using time-series of TerraSAR-X data. Thus, the dynamics of slaking crust hydric states within plots can be monitored using TerraSAR-X data.

French. Cet article analyse le comportement du signal radar TerraSAR-X en HH-25° et HH-50° pour la cartographie et le suivi des caractéristiques du sol, humidité et croute de battance.