Permafrost mapping in the Tibet plateau using polarimetric SAR

Permafrost areas are potentially sensitive indicators of a changing global climate, especially at high latitudes. The Tibetan plateau is as the third pole, the permafrost plays an important role for indicating the climate change. At microwave frequencies, freezing results in a dramatic decrease of the dielectric constant of soil, which significantly decreases their radar backscattering properties. The obvious difference on vegetation between permafrost and non-permafrost area can be detected by SAR images. The radar polarization signature of an object permits a more accurate description of the object of interest than single-polarization measurements. The authors' examine the usage of multi-frequency polarization SAR data to map permafrost in the Tibet plateau. The different classification results show that C-band HH polarimetric and L-band HH, VV polarimetric images can discriminate permafrost with high accuracy. Combined L- and C-bands some polarization items will improve significantly classification accuracy. So the multi-frequency polarization SAR data are fairly good use to map permafrost in the Tibet plateau.