Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 13, 5453-5470, 2016
http://www.biogeosciences.net/13/5453/2016/
doi:10.5194/bg-13-5453-2016
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
30 Sep 2016
Can C-band synthetic aperture radar be used to estimate soil organic carbon storage in tundra?
Annett Bartsch1,2, Barbara Widhalm1,2, Peter Kuhry3, Gustaf Hugelius3, Juri Palmtag3, and Matthias Benjamin Siewert3 1Zentralanstalt für Meteorologie und Geodynamik, 1190 Vienna, Austria
2Vienna University of Technology, 1040 Vienna, Austria
3Stockholm University, Department of Physical Geography, 106 91 Stockholm, Sweden
Abstract. A new approach for the estimation of soil organic carbon (SOC) pools north of the tree line has been developed based on synthetic aperture radar (SAR; ENVISAT Advanced SAR Global Monitoring mode) data. SOC values are directly determined from backscatter values instead of upscaling using land cover or soil classes. The multi-mode capability of SAR allows application across scales. It can be shown that measurements in C band under frozen conditions represent vegetation and surface structure properties which relate to soil properties, specifically SOC. It is estimated that at least 29 Pg C is stored in the upper 30 cm of soils north of the tree line. This is approximately 25 % less than stocks derived from the soil-map-based Northern Circumpolar Soil Carbon Database (NCSCD). The total stored carbon is underestimated since the established empirical relationship is not valid for peatlands or strongly cryoturbated soils. The approach does, however, provide the first spatially consistent account of soil organic carbon across the Arctic. Furthermore, it could be shown that values obtained from 1 km resolution SAR correspond to accounts based on a high spatial resolution (2 m) land cover map over a study area of about 7  ×  7 km in NE Siberia. The approach can be also potentially transferred to medium-resolution C-band SAR data such as ENVISAT ASAR Wide Swath with  ∼  120 m resolution but it is in general limited to regions without woody vegetation. Global Monitoring-mode-derived SOC increases with unfrozen period length. This indicates the importance of this parameter for modelling of the spatial distribution of soil organic carbon storage.

Citation: Bartsch, A., Widhalm, B., Kuhry, P., Hugelius, G., Palmtag, J., and Siewert, M. B.: Can C-band synthetic aperture radar be used to estimate soil organic carbon storage in tundra?, Biogeosciences, 13, 5453-5470, doi:10.5194/bg-13-5453-2016, 2016.
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Short summary
A new approach for the estimation of soil organic carbon (SOC) pools north of the tree line has been developed based on synthetic aperture radar (SAR) data from the ENVISAT satellite. It can be shown that measurements of C-band SAR under frozen conditions represent vegetation and surface structure properties which relate to soil properties, specifically SOC. The approach provides the first spatially consistent account of soil organic carbon across the Arctic.
A new approach for the estimation of soil organic carbon (SOC) pools north of the tree line has...
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