Long- Term P-Band Tomosar Observations from the Borealscat Tower Experiment

SAR tomography at P-band allows the separation of scatterers throughout the vertical extent of a forest canopy, offering a SAR observable that can be used for biomass estimation. But the vertical backscattering distribution of forests are sensitive to changes in the weather and seasons, effects which are poorly understood. In this study, a tower-based radar is used to produce fully-polarimetric tomographic images of a boreal forest at P-band which are analysed over a period of one year. The largest variations seen were due to sub-zero temperatures, causing a drop in the effective scattering height. Seasonal changes in soil moisture and temperature caused a drop in ground-level backscatter at HH-polarisation and a drop in canopy-level cross-polarised backscatter during the summer.