Spatial and temporal variability of net accumulation from shallow cores from vestfonna ice cap (nordaustlandet, svalbard)

Abstract

Beaudon, E., Arppe, L., Jonsell, U., Martma, T., Möller, M., Pohjola, V.A., Scherer, D. and Moore, J.C., 2011. Spatial and temporal variability of net accumulation from shallow cores from Vestfonna ice cap (Nordaustlandet, Svalbard). Geografiska Annaler: Series A, Physical Geography, 93, 287–299. DOI: 10.1111/j.1468‐0459.2011.00439.x

Abstract

We analyse ice cores from Vestfonna ice cap (Nordaustlandet, Svalbard). Oxygen isotopic measurements were made on three firn cores (6.0, 11.0 and 15.5 m deep) from the two highest summits of the glacier located on the SW–NE and NW–SE central ridges. Sub‐annual δ¹⁸O cycles were preserved and could be counted visually in the uppermost parts of the cores, but deeper layers were affected by post‐depositional smoothing. A pronounced δ¹⁸O minimum was found near the bottom of the three cores. We consider candidates for this δ¹⁸O signal to be a valuable reference horizon since it is also seen elsewhere in Nordaustlandet. We attribute it to isotopically depleted snow precipitation, which NCEP/NCAR reanalysis shows was unusual for Vestfonna, and came from northerly air during the cold winter of 1994/95. Finding the 1994/95 time marker allows establishment of a precise depth/age scale for the three cores. The derived annual accumulation rates indirectly fill a geographical gap in mass balance measurements and thus provide information on spatial and temporal variability of precipitation over the glacier for the period spanned by the cores (1992–2009). Comparing records at the two locations also reveals that the snow net accumulation at the easternmost part of Vestfonna was only half of that in the western part over the last 17 years.

Key words:

• accumulation rate
• firn core
• oxygen isotope ratio
• sea ice
• wind anomaly
• Vestfonna

Acknowledgements

We thank the Finnish Forest Research Institute, Rovaniemi Research Unit for the use of cold‐room and clean‐room facilities for the cutting of the core. Financial support was provided by the Finnish Academy and by the Estonian Science Foundation through SvalGlac project and by The Nordic Council of Ministers and IPY‐KINNVIKA. The German contribution to the research presented here was funded by the Deutsche Forschungsgemeinschaft (grants no. SCHE 750/3‐1 and SCHN 680/2‐1), and by the German Federal Ministry of Education and Research (grants no. 03F0623A and 03F0623B).

We acknowledge the Swedish Polar Research Secretariat for the logistic support within the SWEDARCTIC program and the University of Svalbard (UNIS) for the use of the cold room and vehicles. Special thanks to Janne Johansson, Lasse Tano and Åke Wallin for service in the field. We are grateful to Denis Samyn for his important assistance during the drilling operation and we also thank all people involved in IPY‐KINNVIKA fieldwork and fieldwork planning: the ship and personnel of the Norwegian coast guard Svalbard, Naviga and Airlift A/S for their valuable services. The Governor of Svalbard is to be thanked for giving us permission to use the old IPY‐3 station Kinnvika.

Additional information

Notes on contributors

Emilie Beaudon

Emilie Beaudon, Arctic Centre, University of Lapland, P.O. Box 122, 96101 Rovaniemi, Finland Email: [email protected]

Laura Arppe

Laura Arppe, Department of Geosciences and Geography, P.O. Box 64, 00014 University of Helsinki,Finland. Email: [email protected]

Ulf Jonsell

Ulf Jonsell, Department of Earth Sciences, Uppsala University, Sweden; ETSI de Telecomunicación, Universidad Politécnica de Madrid, Avenida Complutense 30, City University, 28040 Madrid Spain. Email: [email protected]

Tõnu Martma

Tõnu Martma, Institute of Geology, Tallinn University of Technology, Ehitajate tee 5 19086 Tallinn, Estonia. Email: [email protected]

Marco Möller

Marco Möller, Department of Geography, RWTH Aachen University, Templergraben 55, 52056 Aachen, Germany. Email: [email protected]‐aachen.de

Veijo A. Pohjola

Veijo A. Pohjola, Department of Earth Sciences, Uppsala University, Villavägen 16, S‐752 36 Sweden. Email: [email protected]

Dieter Scherer

Dieter Scherer, Department of Ecology, Technische Universität Berlin, Rothenburgstrasse 12, 12165 Germany. Email: dieter.scherer@tu‐berlin.de

John C. Moore

John C. Moore, Colleges of Global Change and Earth System Science, Beijing Normal University, 19 Xinjiekou Wai street, Beijing, China,100875. Email: [email protected]