Mariusz Grabiec

SNOWPACK CHARACTERISTICS OF VESTFONNA AND DE GEERFONNA (NORDAUSTLANDET, SVALBARD) – A SPATIOTEMPORAL ANALYSIS BASED ON MULTIYEAR SNOW-PIT DATA

Möller, M., Möller, R., Beaudon, É., Mattila, O.‐P., Finkelnburg, R., Braun, M., Grabiec, M., Jonsell, U., Luks, B., Puczko, D., Scherer, D. and Schneider, C., 2011. Snowpack characteristics of Vestfonna and De Geerfonna (Nordaustlandet, Svalbard) – a spatiotemporal analysis based on multiyear snow‐pit data. Geografiska Annaler, Series A: Physical Geography, 93, 273–285. DOI: 10.1111/j.1468‐0459.2011.00440.x Abstract Extensive glaciological field measurements were carried out on the ice cap Vestfonna as well as on the minor ice body De Geerfonna (Nordaustlandet, Svalbard) within the framework of IPY Kinnvika. Field campaigns were conducted during the period 2007–2010 in spring (April/May) and summer (August). In this study we compile and present snow cover information obtained from 22 snow pits that were dug on Vestfonna during this period. Locations are along two transects on the northwestern, land terminating slope of the ice cap, on its central summit, Ahlmann Summit, and at a set of several other locations in the eastern and northern part of the ice cap. Snow‐cover information acquired from four snow pits on adjacent De Geerfonna is also incorporated in this study. Field data are analysed regarding snow stratigraphy, snow density, snow hardness and snow temperature. Results reveal mean snow densities of around 400 kg m−3 for the snowpack of Vestfonna with no apparent spatial or interannual variability. A distinctly higher value of more than 450 kg m−3 was obtained for De Geerfonna. A spatial comparison of snow water equivalents above the previous end‐of‐summer surface serves for obtaining insights into the spatial distribution of snow accumulation across Vestfonna. Altitude was found to be the only significant spatial parameter for controlling snow accumulation across the ice cap.

Ice Volume Estimates from Ground-Penetrating Radar Surveys, Wedel Jarlsberg Land Glaciers, Svalbard

Abstract We present ground-penetrating radar (GPR)—based volume calculations, with associated error estimates, for eight glaciers on Wedel Jarlsberg Land, southwestern Spitsbergen, Svalbard, and compare them with those obtained from volume-area scaling relationships. The volume estimates are based upon GPR ice-thickness data collected during the period 2004–2013. The total area and volume of the ensemble are 502.91 ± 18.60 km2 and 91.91 ± 3.12 km3, respectively. The individual areas, volumes, and average ice thickness lie within 0.37–140.99 km2, 0.01–31.98 km3, and 28–227 m, respectively, with a maximum recorded ice thickness of 619 ± 13 m on Austre Torellbreen. To estimate the ice volume of unsurveyed tributary glaciers, we combine polynomial cross-sections with a function providing the best fit to the measured ice thickness along the center line of a collection of 22 surveyed tributaries. For the time-to-depth conversion of GPR data, we test the use of a glacierwide constant radio-wave velocity chosen on the basis of local or regional common midpoint measurements, versus the use of distinct velocities for the firn, cold ice, and temperate ice layers, concluding that the corresponding volume calculations agree with each other within their error bounds.

Modeling and Hindcasting of the Mass Balance of Werenskioldbreen (Southern Svalbard)

Abstract The authors propose a model of glacial mass balance based on correlations with meteorological observations and data from climate re-analysis. The minimum input data required include the following: average monthly temperature on the glacier and in its vicinity during summertime for a reference time period, average monthly air temperature, and average precipitation total at the nearest weather station or from re-analysis. This model was used to hindcast the mass balance and its components at Werenskioldbreen (southern Svalbard) over the period 1912–2005. The hindcast specific mass balance was then used to estimate the change in the thickness of the snout of Werenskioldbreen over the period 1958–1990. These results were compared with results obtained using a cartographic method. Comparing the topographic maps, the glacier front lowered 28.7 m on average over 32 years. The average difference in the calculation of the change in glacier thickness between these two methods amounted to 3.7 m (based on meteorological data) and 0.2 m (using ERA-40). The discrepancy of less than 13% confirmed that the method is a reasonably accurate way of predicting past glacier mass balance. The proposed method can find a broad application in hindcasting the mass balances of small Svalbard glaciers where observation data are scarce or nonexistent.

Coast formation in an Arctic area due to glacier surge and retreat: the Hornbreen - Hambergbreen case from Spistbergen

Glacierized coasts undergo faster geomorphic processes than unglaciated ones. We have studied changes of the coastal area in southern Svalbard with the glacier bridge between Torell Land and Sorkapp Land since the beginning of the 20th century. The existence of a continuous subglacial depression beneath the Hornbreen–Hambergbreen system has been debated since the 1960s, with inconclusive results. In this study we assess both the subglacial topography and the bathymetry of Hornsund Fjord and Hambergbukta bay. This included ~40 km of radar surveys over the glacial system and sea depth sounding. The extent of the glaciers from maps and satellite images together with digital terrain models and surface elevation data based on GPS profiling were used to analyse geometry changes of the glacier surfaces. The results confirm the existence a continuous subglacial depression below sea level (c. 40 m deep) between Hornsund and the Barents Sea. The Hornbreen-Hambergbreen system has changed in shape over the past century, reflecting its dynamic origin and activity, also exemplified by the sequential surges identified since 1899. There was a pre-surge build-up event of Flatbreen causing a surge and subsequent lowering of the Hornbreen-Hambergbreen terminus by the 1960s. After, the entire surface lowered, albeit with a delay in the Hornbreen terminal zone. Since the year 2000, Hornbreen terminus has retreated at an average rate of 106 m a-1; ~50% faster than that of Hambergbreen. If the retreat continues at the 2000 – 2015 average rate, the ice bridge between Hornsund and Hambergbukta will be broken sometime between 2055 and 2065 and the Hornsund strait will separate Sorkapp Land from the Spitsbergen island. The processes and events described in this study, particularly the effects of the glacier surge, may provide a model for changes likely to occur in other coastal glaciated regions experiencing rapid change.

Snow deposition patterns on southern Spitsbergen glaciers, Svalbard, in relation to recent meteorological conditions and local topography

ABSTRACT We present a detailed study on snow cover on six different glaciers in southern Spitsbergen, Svalbard: Amundsenisen, Flatbreen, Hansbreen, Nannbreen, Storbreen and Werenskioldbreen. Fieldwork was carried out in April–May 2013, at the end of the accumulation season, to determine large-scale spatial distribution patterns of snow cover on glaciers surrounding the Hornsund Fjord. Snow depth was measured using an 800 MHz ground-penetrating radar (GPR). In addition, the structure of the snowpack was determined by digging snow pits and collecting snow cores from different glacier facies. These samples were subsequently analysed against circulation types and meteorological data from selected sites. In particular, snow patterns were compared against rain-on-snow events. The mean snow depth measures ranged from 1.90 m (Werenskioldbreen) to 3.80 m (Amundsenisen), whereas the accumulation gradient ranged from 15 cm 100 m−1 (Storbreen) to 74 cm 100 m−1 (Nannbreen). These results followed previous observations, suggesting a decrease in snow accumulation from coastal areas towards the island’s interior. The estimated snow water equivalent values were lower than those measured in the 1990s and during 2010 (Hansbreen: c. −48%), with the exception of Amundsenisen (c. +17%). The relatively high densities found in the snowpack did not compensate for the shallow snow depths measured, which can be ascribed to low precipitation totals and an increased frequency of rain events during the winter months.