Vortrag, 4. TerraSAR-X Science Team Meeting, Oberpfaffenhofen: 14.02.2011 - 16.02.2011
Abstract:
Surface roughness is an important land surface parameter which influences energy and water exchange between the Earth and the atmosphere. It is also a relevant parameter for hydrological modeling since it influences the velocity of surface runoff and the soil moisture content. The semi-arid environment of the Tibetan Plateau features only a sparse vegetation cover. Surface roughness is relatively stable during the year since the surface is not affected by tillage or other intensive human activity. In order to characterize surfaces with various soil micro-structures, a number of homogeneous test plots were identified in the vicinity of Nam Co Research station in Central Tibet. These plots represent sandy, gravel, stony and hummocky surfaces. Three methods were used for ground roughness measurements: pin-meter, chain method and close range photogrammetry in order to estimate RMS height, auto-correlation length and Saleh Roughness Factors (SRF). Profiles from 1 to 10 meters were measured in order to assess the influence of profile length on the roughness variables. The ground roughness measurements were compared with backscattering coefficients extracted from dual polarization TerraSAR-X Stripmap images.