TUTORIAL ON SAR POLARIMETRY

Description of natural surfaces 1. DESCRIPTION OF NATURAL SURFACES Earth's solid surface represents an essential part of our ecosystem and because of its diversity a huge number of bio- & geo-physical parameters is required for its detailed description and/or monitoring. An important element of the earth's surface is the soil. Soils can be parameterised in terms of its consistency, and its dielectric and geometric properties. The dielectric properties of soils are expressed - apart from its consistency - primarily by its moisture content. On the other hand, the soil roughness describes the geometric characteristics of the soil surface. Classical methods in soil physics are based on point measurements to estimate these two surface parameters. The most critical factor, besides the enormous time and working effort, is the extrapolation of point samples to catchment (or sub-regional) scale processes. The greatest error in the parameterisation occurs on the interface between different scales of hydrological to climatic or ecological models. Such mismatch problems have an important implication for the credibility of impact studies driven by the output of models. In order to bridge the scales between different science applications, e.g. climate hydrology and ecology models, methods for both observing and representing sub-grid-scale heterogeneity, as well as linking parameter/state variables across disparate scales, are in great need. However, remotely sensed ...