ice avalanches. A prominent example of a present regenerated glacier is
Morsarj€ okull in south Iceland. Morsarj€ okull lost its connection with Vatnaj€ okull
in recent times (Barry and Gan 2011).
Once the tongue of Pasterze Glacier is separated from the upper part of the
glacier, ice-flow movement pointing down-valley will decrease eventually to zero.
This will presumably not be the case for the ice movement towards the valley center
assuming further topographical changes due to differential ablation. The areal
extent of the supraglacial debris cover and the debris thickness will further increase
if we project the evolution seen between 1964 and 2009 into the future. In 1964,
21.0 % of the glacier tongue was debris-covered (Kellerer-Pirklbauer et al. 2008)
whereas 45 years later this percentage had increased to 72.1 %.
9.6 Conclusions and Outlook
The high resolution photographs of 2003, 2006 and 2009 allowed the preparation of
base data, i.e. DEMs, orthophotos and glacier boundaries, needed for the anticipated glaciological and geomorphological studies. This base data helped us to
quantify important glacial and paraglacial processes associated with the recession
of Pasterze Glacier. We applied the geodetic method for glacier mass balance
measurements for the period 2003–2009. Our results correspond very well with
the annual mass balance measurements carried out by ZAMG (2013) using the
glaciological method, keeping in mind the limitations of both methods (Fischer
2011). Our study gives clear evidence that Pasterze Glacier is far from equilibrium.
Furthermore, we demonstrated that the icefall connecting the glacier tongue with
the main glacier is rapidly disintegrating. We thus assume that the remaining glacier
tongue will turn into a large dead ice body in the near future. However, the
supraglacial debris cover will most likely increase in extent and thickness, hence
reducing the ablation rate. The evaluation of further aerial surveys (e.g. 2012) is
planned in order to continue the high resolution glacier monitoring. We presented a
selection of possible evaluations of the base data. Exemplary fields of interest in
further studies could be: (a) in-depth analysis of surface flow pattern, (b) analysis of
ice collapse structures, and (c) mapping and quantifying paraglacial landforms and
processes in recently deglaciated areas.
Acknowledgments The aerial photographs of 2003 were made available by Heinz Slupetzky and
the Hydrological Service of the Regional Government of Salzburg. Photogrammetric work was
financially supported by the Austrian Federal Ministry of Science and Research and the Salzburg
Hydrological Service. The aerial photographs of 2009 were provided free of charge by the
Department of Geoinformation of the Regional Government of Tyrol (TIRIS). Field campaigns
at Pasterze Glacier were supported by the project ‘ALPCHANGE – Climate change and impacts in
southern Austrian alpine regions’ funded by the Austrian Science Fund (FWF) through project
FWF P18304-N10 and by the Austrian Alpine Club (OeAV) within the framework of the annual
glaciological surveys. VERBUND-Austrian Hydro Power provided meteorological data from the
automatic weather station AWS-MA. An anonymous reviewer is very much thanked for his
constructive criticism on an earlier version of this paper.
9 Glaciological Studies at Pasterze Glacier (Austria) Based on Aerial Photographs
195
Morsarj€ okull in south Iceland. Morsarj€ okull lost its connection with Vatnaj€ okull
in recent times (Barry and Gan 2011).
Once the tongue of Pasterze Glacier is separated from the upper part of the
glacier, ice-flow movement pointing down-valley will decrease eventually to zero.
This will presumably not be the case for the ice movement towards the valley center
assuming further topographical changes due to differential ablation. The areal
extent of the supraglacial debris cover and the debris thickness will further increase
if we project the evolution seen between 1964 and 2009 into the future. In 1964,
21.0 % of the glacier tongue was debris-covered (Kellerer-Pirklbauer et al. 2008)
whereas 45 years later this percentage had increased to 72.1 %.
9.6 Conclusions and Outlook
The high resolution photographs of 2003, 2006 and 2009 allowed the preparation of
base data, i.e. DEMs, orthophotos and glacier boundaries, needed for the anticipated glaciological and geomorphological studies. This base data helped us to
quantify important glacial and paraglacial processes associated with the recession
of Pasterze Glacier. We applied the geodetic method for glacier mass balance
measurements for the period 2003–2009. Our results correspond very well with
the annual mass balance measurements carried out by ZAMG (2013) using the
glaciological method, keeping in mind the limitations of both methods (Fischer
2011). Our study gives clear evidence that Pasterze Glacier is far from equilibrium.
Furthermore, we demonstrated that the icefall connecting the glacier tongue with
the main glacier is rapidly disintegrating. We thus assume that the remaining glacier
tongue will turn into a large dead ice body in the near future. However, the
supraglacial debris cover will most likely increase in extent and thickness, hence
reducing the ablation rate. The evaluation of further aerial surveys (e.g. 2012) is
planned in order to continue the high resolution glacier monitoring. We presented a
selection of possible evaluations of the base data. Exemplary fields of interest in
further studies could be: (a) in-depth analysis of surface flow pattern, (b) analysis of
ice collapse structures, and (c) mapping and quantifying paraglacial landforms and
processes in recently deglaciated areas.
Acknowledgments The aerial photographs of 2003 were made available by Heinz Slupetzky and
the Hydrological Service of the Regional Government of Salzburg. Photogrammetric work was
financially supported by the Austrian Federal Ministry of Science and Research and the Salzburg
Hydrological Service. The aerial photographs of 2009 were provided free of charge by the
Department of Geoinformation of the Regional Government of Tyrol (TIRIS). Field campaigns
at Pasterze Glacier were supported by the project ‘ALPCHANGE – Climate change and impacts in
southern Austrian alpine regions’ funded by the Austrian Science Fund (FWF) through project
FWF P18304-N10 and by the Austrian Alpine Club (OeAV) within the framework of the annual
glaciological surveys. VERBUND-Austrian Hydro Power provided meteorological data from the
automatic weather station AWS-MA. An anonymous reviewer is very much thanked for his
constructive criticism on an earlier version of this paper.
9 Glaciological Studies at Pasterze Glacier (Austria) Based on Aerial Photographs
195