Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
doi:10.5194/tcd-5-565-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
14 Feb 2011
Review status
This discussion paper has been under review for the journal The Cryosphere (TC). The revised manuscript was not accepted.
Comparison of direct and geodetic mass balances on an annual time scale
A. Fischer1, H. Schneider2, G. Merkel3, and R. Sailer4 1Institute of Meteorology and Geophysics, University of Innsbruck, Austria
2Institute of Mathematics, University of Innsbruck, Austria
3Faculty of Geoinformation, University of Applied Sciences – Fachhochschule München, Germany
4Institute of Geography, University of Innsbruck, Austria
Abstract. Very accurate airborne laserscanning (ALS) elevation data was used to calculate the annual volume changes for Hintereisferner and Kesselwandferner in the Ötztal Alps, Austria for 2001/2002–2008/2009. The comparison of the altitude of 51 recently GPS surveyed ground control points showed that the accuracy of the ALS DEMs is better than 0.3 m. The geodetic mass balance was calculated from the volume change using detailed maps of the firn cover and applying corrections for the seasonal snow cover. The maximum snow height at the time of the elevation data flight was 0.5 m averaged over the glacier surface. The volume change data was compared to in situ mass balance data for the total area and at the stakes. For the total period of 8 yr, the difference between the geodetic and the direct mass balance is 2.398 m w.e. on Hintereisferner and 1.380 m w.e. on Kesselwandferner, corresponding to about two times the mean annual mass balance. The vertical ice flow velocity was measured and found to be on the same order of magnitude as the mass balance at KWF. This is an indicator that volume change data does not allow the calculation of ablation or accumulation rates without detailed measurements or models of the vertical ice flow velocity. Therefore, only direct mass balance data allow process studies or investigation of the climatic controls of the resulting mass changes.

Citation: Fischer, A., Schneider, H., Merkel, G., and Sailer, R.: Comparison of direct and geodetic mass balances on an annual time scale, The Cryosphere Discuss., 5, 565-604, doi:10.5194/tcd-5-565-2011, 2011.
A. Fischer et al.
A. Fischer et al.

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