Science Service System

Summary of Proposal RES3359

TitleNovel method for monitoring peat-soil subsidence based on radar remote sensing
Investigator Fakhri, Falah - natural resources institute Finland (luke), Management and production of renewable resources
Team Member
professor Regina, Kristiina - natural resources institute Finland (luke), Management and production of renewable resources
SummaryIntroduction Peatlands represent a major store of soil carbon and sink for carbon dioxide (CO2). Northern peatlands store 450 billion t carbon which is equivalent to one third of global soil C stocks and 75% of the pre-industrial C in the atmosphere [1]. Greenhouse gas (GHG) emissions from peat soils are a concern for Finland since 10% of total emissions or 60% of agricultural emissions originate from decomposition of cultivated peat. These emissions are calculated for the statistics using the emission factors of the Intergovernmental Panel on Climate Change. However, these factors are based on measurements of only few fields and the uncertainties are among the highest of the source classes. Measurement of GHGs is expensive and thus verification of the suitability of the emission factors with remote sensing would be a cost-saving option to improve the quality of emission inventories. Modern remote sensing techniques have made it possible to detect and monitor ground deformation in millimeter scale precision. This new geodetic technique calculates the interference pattern caused by the difference in phase between two images acquired by space-borne synthetic aperture radar at two distinct times [2]. Both Envisat C-band and ALOS L-band were used to monitor changes in peat height in the tropics [3]. InSAR techniques have been applied also in studying the degradation of Dutch pasturelands [4] but to my knowledge they have not been applied in Finland for peatland. Study objectives and application of the results This study focuses on testing the idea of using the SAR Interferometry (InSAR) techniques for monitoring subsidence of cultivated peat soils in Finland. Different radar bands will be used and manipulated via varying InSAR techniques, to select the best one to estimate the peatland movement on sites where CO2 emissions, subsidence or peat properties have been measured. The observed subsidence will be converted to estimates of CO2 emission using data on peat properties and the remote sensing results will be compared with field study results. If the two estimates are in agreement, the results will be used to develop a method that could be combined to GHG modelling in future projects. Eventually this method could be used in wider scale to evaluate the quality of the national GHG inventory results or even to replace the current method. In the future, the idea can be developed further towards a countrywide estimation method in cooperation e.g. with the Finnish Meteorological Institute, Geological Survey of Finland or University of Helsinki. Publication plan one peer-reviewed scientific paper will be prepared.

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DLR 2004-2016