Seasonal and spatial variability of surface hydraulic properties

Abstract

Monitoring, using remote sensing, of seasonal changes of land surface properties such as: freezing and thawing of wetland, freezing and thawing of soil, as well as soil moisture and snow cover mapping, relies on capabilities to relate physical characteristics of the study area and satellite observations. The water and ice content of soil are very important parameters for determination of the storage capacity and hydraulic properties of the surface. Thus, the objective of this work was to derive indices that would provide link between remote sensing observations and regional/seasonal variability of surface properties. Radiative transfer and radar backscatter models were configured to simulate and analyse the link between surface properties, atmospheric conditions, and the signals measured by active and passive sensors. In this work we present the results of model simulation of microwave backscattering for different land surface types e.g., wetland, forest cover. Several different study sites were selected in Ontario. RADARSAT (Fall, Winter, and Spring) images, at different resolution, were acquired for several different sites in Northern and Southwest Ontario. Two independent transitions corresponding to soil thaw and possible canopy thaw were revealed by the data. Analysis of Radarsat scenes indicates shifts in radar backscatter related to varying environmental conditions during image acquisition, e.g.,snow storm. Consequences of such effects on the analysis of surface characteristics can be significant.