Markus Eckerstorfer

Central Svalbard 2000–2011 Meteorological Dynamics and Periglacial Landscape Response

Abstract Local mountain meteorology of the landscape around Longyearbyen in central Svalbard is analyzed through the decade from 2000 to 2011. Standard meteorological stations from close to sea level and up to 464 m a.s.l. located on different periglacial landforms, have been used. During winters with little sea ice, strong temperature inversions do not develop, and then there is a distinct cooling with height, as opposed to when sea ice is present. Airflow is accelerated due to topography and direction deflected in the confined valleys, whereas open plateaus have on average 1 m/s lower wind speeds with a regional SE direction. The permafrost thermal state is largely controlled by meteorology, with permafrost in the valley bottoms as cold as on the mountain plateaus. The periglacial landform most exposed to climatic variability is ice-wedges, which seem to crack mainly during shorter cooling periods. Such activity is also linked to temperature inversions, and thus also occur mainly when sea ice is present. Solifluction is mainly controlled by the balance between summer thawing and winter freezing in combination with snow dynamics, whereas avalanches are mainly wind controlled. Avalanches and avalanche controlled landforms are least sensitive to climatic variability.

The ''High Arctic Maritime Snow Climate'' in Central Svalbard

Abstract In this first systematic classification of the snowpack in central Svalbard a new additional snow climate is presented. Based on field observations in the 2007–2009 period, 109 snow pits were quantitatively analyzed in terms of temperature gradients, grain shapes, grain sizes, and hardness of every snow layer. Emphasis was given to the occurrence of depth hoar, ice layers, the most observed weak layer–bed surface interfaces. These parameters in combination with meteorological observations define the “High Arctic maritime snow climate” as having a very thin and cold snowpack, a basal layer of depth hoar with winds labs and ice layers on top. The snowpack lasts for 8–10 months of the year, at higher grounds for the whole year. Snow climate classifications are an important part of improving the local avalanche characterization. This is timely, especially for the area around Svalbards main settlement Longyearbyen, where avalanches represent a natural hazard. Also, climate models for the area predict changing meteorological conditions, especially more solid precipitation, thus a description of the snow climate as it is today is important. This “High Arctic maritime snow climate” characterization is based on the 16.8 km2 mountainous area around Longyearbyen at 78°N, and does not fit any other High Arctic location. Svalbard has in comparison to other High Arctic locations milder climate due to an overall meteorological maritime influence.

Comparison of geomorphological field mapping and 2D-InSAR mapping of periglacial landscape activity at Nordnesfjellet, northern Norway: Comparison of geomorphological field- and 2D InSAR mapping

The ability to continuously monitor the dynamic response of periglacial landforms in a climate change context is of increasing scientific interest. Satellite radar interferometry provides information on surface displacement that can be related to periglacial processes. Here we present a comparison of two-dimensional (2D) surface displacement rates and geomorphological mapping at periglacial landform and sediment scale from the mountain Nordnesfjellet in northern Norway. Hence, 2D Interferometric Synthetic Aperture Radar (InSAR) results stem from a 2009–2014 TerraSAR-X dataset from ascending and descending orbits, decomposed into horizontal displacement vectors along an east–west plane, vertical displacement vectors and combined displacement velocity. Geomorphological mapping was carried out on aerial imagery and validated in the field. This detailed landform and sediment type mapping revealed an altitudinal distribution dominated by, weathered bedrock blockfields, surrounded primarily by slightly, to non-vegetated solifluction landforms at the mountain tops. Below, an active rockslide and associated rockfall deposits are located on the steep east-facing side of the study area, whereas glacial sediments dominate on the gentler western side. We show that 2D InSAR correctly depicts displacement rates that can be associated with typical deformation patterns for flat-lying or inclined landforms, within and below the regional permafrost limit, for both wet and dry areas. A net lowering of the entire landscape caused by general denudation of the periglacial landforms and sediments is here quantified for the first time using radar remote sensing. Copyright