Scale-dependent roughness of a glacier surface: Implications for radar backscatter and aerodynamic roughness modelling

Abstract

The roughness of the snow-free surface of the glacier midre Lovénbreen, Svalbard, has been investigated on scales between 1 mm and 300 m. It is shown that the roughness is reasonably well described by scale-free (fractal) models for scales longer than a few metres and shorter than about 100 mm. However, there is a break in the behaviour between these scales which can be characterized by a definite scale length of 70-500 mm and a root-mean-square height variation between around 6 and 70 mm. The aerodynamic roughness length contributed by these features is estimated to be 0.3-1.5 mm. Features on this scale are consistent with the observed microwave backscattering properties of the glacier.