Use of ERS/SAR measurements for soil geometric and aerodynamic roughness estimation in semi-arid and arid areas

This paper discusses the potential of radar signal to characterise the bare surface roughness in arid or semi-arid regions. The used microwave sensor is the SAR of ERS. Ground truth measurements were acquired over different arid sites in the South of Tunisia. An empirical approach is proposed to derive the surface roughness from SAR measurements. The relationships with two different kinds of roughness have been studied: the geometric roughness, which is characterised by a rather new parameter called Zs, and the classical aerodynamic roughness Z₀.