Topography effects on the L-band emissivity of soils: TuRTLE 2006 field experiment

The impact of topography on soil emissivity at L-band is not well known. In order to provide data to assess this issue, the Topography effects on RadiomeTry at L-band Experiment (TuRTLE) 2006 was carried out in a mountainous area about 50 km North of Barcelona (Spain). Radiometric measurements covering the mountain slope, and up to the sky were acquired. Concurrently, ground-truth and meteorological data were registered. Radiometric measurements have been compared to the emissivity obtained by simulation using a facet model which considers the high resolution digital elevation model and land cover map of the area. Polarization mixing due to surface tilting and integration over the antenna pattern have also been included in the simulator, and results agree with the radiometric measurements. The largest discrepancies occur for an almost bare soil at large local incidence angles and H-polarization, close to the radiometer, which suggests that further modeling work is still needed.