Norut installs solifluction station
Norut installs solifluction station
Last week Norut installed a solifluction monitoring station recording downhill movement of soil at the Nordnes mountain in Troms county. See the building of the station here.
Between 14 – 18 August 2013, Norut research scientist Markus Eckerstorfer and Fraser Smith from University of Dundee, Scotland, installed a solifluction monitoring station at Nordnes. The station will allow real-time knowledge about horizontal and vertical movements of the permafrost soil, associated with freezing and thawing processes.
Solifluction can affect stability of infrastructure
Solifluction is the process of slow, downhill movement of soil, caused by freezing and thawing processes in areas with frozen ground. Solifluction lobes are one of the most widespread periglacial landforms, found in areas where freezing and thawing of water saturated soils occur.
"Knowledge of such processes is important, as thawing permafrost is associated with ground displacement causing problems for infrastructure, as well as process-speed up leading to natural hazards", tells Markus Eckerstorfer.
The station was raised in three days. See the building process in two minutes here:
Installation of real-time solifluction monitoring station.
Station located in area with discontinous permafrost
For the location of the station, a well-defined, active solifluction lobe, underneath a perennial snowpatch was chosen. The location is at about 700 m a.s.l., most likely in patchy, discontinuous permafrost.
The solifluction monitoring station has a 2 x 2 m steel frame that is anchored in the ground so that it does not move with the solifluction movement. On the steel frame, two LVTD´s (linear variable differential transformers) are mounted, allowing the measurement of ground displacement with an accuracy of 1.5 mm (Harris et al., 2007).
Additionally, ground temperatures, soil moisture and pore water pressure are measured at different depths and locations close to the station.
This solifluction monitoring station is the 5th station that exists worldwide. Two are located in southern Norway and two are located in Svalbard. Thus, an interesting gradient from continuous permafrost at Svalbard to discontinuous and patchy mountain permafrost is covered.
Using satellite radar data for upscaling
This work is done as part of the NFR-funded research project PermaSAR "SAR detection of permafrost landscape changes in northern Norway and Svalbard (2012-2014)", with partners Norut, UNIS, and Åknes/Tafjord beredskap.
One of the main tasks in the project is to use satellite interferometry (InSAR) to produce surface deformation maps over permafrost areas, associated with ground freezing and thawing.
"We aim to compare field monitoring with high-resolution TerraSAR-X and Radarsat-2 satellite data. By doing so, we hope to acquire a better understanding of the interannual variability of ground surface displacement in permafrost areas", tells Eckerstorfer.
The satellite InSAR data allows upscaling of the point-based field measurement.
Harris, C., Kern-Luetschg, M., Christiansen, H.H. and Smith, F., 2011. The Role of Interannual Climate Variability in Controlling Solifluction Processes, Endalen, Svalbard. Permafrost and Periglacial Processes, 22(3): 239-253.10.1002/ppp.727
Harris, C., Luetschg, M., Davies, M.C.R., Smith, F., Christiansen, H.H. and Isaksen, K., 2007. Field instrumentation for real-time monitoring of periglacial solifluction. Permafrost and Periglacial Processes, 18(1): 105-114
Lauknes, T.R., Christiansen, H.H., Eckerstorfer, M. and Larsen, Y., 2013. InSAR detection of permafrost landform dynamics at Kapp Linné central Svalbard, EGU General Assembly 2013. Geophysical Research Abstracts, Vienna, Austria.