Assessment of Fully Polarimetric Biomass Data Over Permafrost

Kurzfassung

In the northern Hemisphere about 15 % of the landmass is underlain by permafrost. With increasing temperatures these permafrost regions become vulnerable to thaw. Permafrost thaw have major impacts on the local ecosystem and can also influence the global climate by the mobilization of organic carbon. The large amount of this stored soil organic carbon (SOC) as well as the observed strong increase in Arctic temperatures (Arctic amplification) can lead to strong positive feedback effects with dramatic consequences for the global climate. The intensity and timing of the permafrost carbon contribution to the global budget is not well constrained and has large uncertainties. In this study we explore polarimeric and interferometric P-band data over wider permafrost regions and will asses the information content of these multi-modal imaging capabilities. The ESA's BIOMASS mission is the first spaceborne P-band Synthetic Aperture Radar (SAR) capable of continuous operation in quad-polarimetric interferometric and/or tomographic mode with a non-zero spatial baseline. BIOMASS data are characterised by the high penetration capability inherent to the P-band. The first BIOMASS data indicated that, in addition to the primary mission objectives focusing on forest carbon dynamics and the secondary objectives addressing ice sheets and arid regions, the data could be of interest to a wider range of applications. Assessing permafrost regions and features is one of the new appealing applications and will be explored with statistical and model-based approaches. We will investigate wider regions in the arctic ranging from Alaska, Northern Canada and Siberia. One of our main study region is located on the northern Taymyr Peninsula in Siberia (Russia) and spans from 75◦N to 78◦N in latitude and 98◦E to 106◦E in longitude. The relief is low to moderate. The climate is characterised as polar Arctic with a mean annual air temperature of about -14◦C. The mean July temperatures are 5 to 6 ◦C. During winter the region experiences monthly mean temperatures below -30 ◦C [16]. The area is underlain by continuous permafrost, with estimated permafrost temperatures of -8◦C. The main reason for this choice is the availability of some reference data that recorded a high increase of hillslope thermokarst, namely retrogressive thaw slumps (RTS), that are strong indicators of atmospheric warming in the least couple of year. Using P-band data we would like to see if these features can retrieved.

P. Bernhard, S. Zwieback, S. Leinss, and I. Hajnsek, “Mapping retrogressive thaw slumps using single-pass tandem-x observations,” IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 13, pp. 3263–3280, 2020