Bernhard Hynek | ZAMG - Academia.edu (original) (raw)

Papers by Bernhard Hynek

Global warming and glacier retreat are affecting the morphodynamics of proglacial rivers. In resp... more Global warming and glacier retreat are affecting the morphodynamics of proglacial rivers. In response to changing hydrology, their altered hydraulics will significantly impact future glacifluvial erosion and proglacial channel development. This study analysis proglacial channel evolution processes at the foreland of Austria's biggest glacier Pasterze by predicted runoff until 2050. A high-resolution digital elevation model was created by an unmanned aerial vehicle, channel bathymetry was sampled, a one-dimensional hydrodynamic-numerical model was generated, and bedload transport formulas were used to calculate the predicted transport capacity of the proglacial river. Due to the fine sediment composition near the glacier terminus (d 50 < 49.6 mm), the calculation results underline the process of headward erosion in the still unaffected, recently deglaciated river section. In contrast, an armor layer is already partly established by the coarse grain size distribution in the already incised river section (d 50 > 201 mm). Furthermore, already reoccurring exposed non-fluvial grain sizes combined with decreasing flow competence in the long term are indicators for erosion-resistant pavement layer formation and landform decoupling in the vertical direction. The presented study clearly shows that subsystems of 'developed channels' exhibiting pavement formation of non-fluvial deposits are found at the investigated glacier foreland. Thus, an extension accompanied by a refinement of the fluvial system in the sediment cascade approach was developed as a central result.

A third glacier inventory (GI3) is presented for the province of Salzburg where 173 glaciers are ... more A third glacier inventory (GI3) is presented for the province of Salzburg where 173 glaciers are located in the seven mountain ranges: Ankogel (47°4'N, 13°14'E), Glockner, Granatspitz, Sonnblick (Goldberg), Hochkönig, Venediger and Zillertal (47°8'N, 12°7'E). The basis for the new GI3 are orthophotos of 2007 and 2009 and the digital elevation model (DEM) of the southern part of Salzburg. On the basis of former inventories, area- and volume changes have been calculated. The biggest relative loss of glacier area per mountain range was found in the Ankogel range and on Hochkönig as a result of the disrupted structure of their small and thin glaciers. In terms of absolute values, the largest changes took place in the Glockner- and Venediger range with an area loss of -10.1 km**2 and -9.7 km**2 during the period between GI1 (1969) and GI3 (2007/2009), respectively. Volume changes have been calculated for nearly half of the glacier area in Salzburg, where DEMs were available. The Glockner, Granatspitz and Sonnblick mountain ranges showed a volume loss of -0.481 km**3 which corresponds to a mean thickness change of -10.5 m. An extrapolation of these changes to all of the 173 glaciers in Salzburg results in a loss of about 1.04 km**3 between GI1 and GI3 and 0.44 km**3 between GI2 and GI3. Overall annual changes in the province of Salzburg between GI2 and GI3 were higher than between GI1 and GI2 and show likewise changes such as those of Tyrol.

eco.mont (Journal on Protected Mountain Areas Research), 2014

Glaciers are important and fast changing landscape elements in Hohe Tauern National Park (HTNP). ... more Glaciers are important and fast changing landscape elements in Hohe Tauern National Park (HTNP). In 1998, 10% of the HTNP area was covered with ice, less than half of the glaciated area during the Little Ice Age maximum. Glaciological monitoring includes mass balance measurements, glacier inventories, length change records and flow velocity measurements, complemented by climatological, hydrological and dendrochronological observations. All these data evidence the climate and glacier history of HTNP in an outstanding way, comparable to few other sites in the world.

The Cryosphere, 2013

Glacier-wide mass balance has been measured for more than sixty years and is widely used as an in... more Glacier-wide mass balance has been measured for more than sixty years and is widely used as an indicator of climate change and to assess the glacier contribution to runoff and sea level rise. Until recently, comprehensive uncertainty assessments have rarely been carried out and mass balance data have often been applied using rough error estimation or without consideration of errors. In this study, we propose a framework for reanalysing glacier mass balance series that includes conceptual and statistical toolsets for assessment of random and systematic errors, as well as for validation and calibration (if necessary) of the glaciological with the geodetic balance results. We demonstrate the usefulness and limitations of the proposed scheme, drawing on an analysis that comprises over 50 recording periods for a dozen glaciers, and we make recommendations to investigators and users of glacier mass balance data. Reanalysing glacier mass balance series needs to become a standard procedure for every monitoring programme to improve data quality, including reliable uncertainty estimates.

EGU General Assembly Conference Abstracts, Apr 1, 2018

Annals of Glaciology, 2009

Global warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to ma... more Global warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to mass-balance investigation, the determination and monitoring of total glacial ice volume and ice-thickness distribution are important parameters for understanding the interactions between climate and the complex glacier system. Because of spatially irregular and sparse datasets, scaling of volume and ice-thickness distribution is often a challenging problem. This study focuses on two small (<2 km 2 ) temperate glaciers in the Hohe Tauern (Eastern Alps) region of central Austria. The period 2003-04 saw the first use of ground-penetrating radar (GPR) to determine the total ice volume and ice-thickness distribution of the two glaciers. A centre frequency of 20 MHz was used in point measuring mode. Despite variable data quality, bedrock reflections up to depths of >100 m were identified in the data. The acquired GPR data are irregularly distributed and the spatial density is too low to calculate reasonable bedrock topography with standard interpolation approaches. Thus one main focus of this study was to develop an appropriate interpolation technique. Eventually, kriging technique and a glacial mechanically based interpolation parameter were used. Mean calculated ice thicknesses for the two investigated glaciers are 40-50 m, with a maximum of 150-165 m. No direct validation data are available, so different considerations support the computed bedrock topography.

Annals of Glaciology, 2008

A detailed model of Alpine surface processes is used to simulate the amount of preferential depos... more A detailed model of Alpine surface processes is used to simulate the amount of preferential deposition as well as redistribution of snow due to snowdrift for two alpine glaciers (Goldbergkees and Kleinfleißkees, Austrian Alps). The sequence of snow-cover modelling consists of the simulation of the wind field with a mesoscale atmospheric model, a three-dimensional finite-element drift module, an energy-balance module and a snowpack module. All modules with the exception of the wind-field model are integrated within the Alpine3D model frame. The drift module of Alpine3D distinguishes between saltation and suspension and is able to capture preferential deposition of snow precipitation and redistribution of previously deposited snow. Validation of the simulated snow depth is done using the spatially dense snow-probing dataset collected during a campaign in May 2003. Simulated snow depths agree with measurements during winter 2002/03 at locations with detailed snow-height monitoring, taking into account the high spatial variability of snow depth on the glacier. Moreover, comparison of snow accumulation from model results with detailed probing on 1 May 2003 for the total glacier area shows that Alpine3D is able to capture major patterns of spatial distribution of snow accumulation. For the first time, the Alpine3D approach of using high-resolution wind fields from a meteorological model and a physical description of snow transport could be validated for a very steep glacierized area and for a full accumulation season. The results show that drift is a dominant factor to be considered for detailed glacier mass balances. Another dominant factor not considered in this study may be snow redistribution due to avalanches.

The paper describes the glaciohydrological monitoring in the region of Rauriser Sonnblick, which ... more The paper describes the glaciohydrological monitoring in the region of Rauriser Sonnblick, which is charcterised by long-term, comprehensive measurements of the glacier mass balance, the glacial discharge and the spatial distribution of precipitation and snow height. All investigated glaciers are less than 1.5 km2 in size. Annual precipitation in the Sonnblick region is high compared to another well established glacier monitoring in Austria (Rofenarche region, Tyrol). Thus climate sensitivity of glaciers in the Sonnblick region is much higher compared to the Rofenarche area. The analysis of available monitoring data from Sonnblick region reveals the high significance of the Alpine crest as a distinct climate divide. Consequently, winter accumulation is much more pronounced at Goldbergkees (north of the Alpine crest) compared to the Wurtenkees or Fleißkees which are situated south of the Alpine crest. Results from recently performed ice thickness measurements show values between approximate 80 to 150 m maximum ice thickness. The today status of the glacier monitoring in the Sonnblick-region is especially valuable for the calibration and validation of glaciohydrological models. In diesem Beitrag wird das glazialhydrologische Monitoring im Bereich der Rauriser Arche (Rauriser Sonnblick) beschrieben. Das Monitoring zeichnet sich durch langjährige und umfangreiche Messungen der Gletschermassenbilanz, des Glazialabflusses und der räumlich verteilten Niederschlagmenge und der Schneehöhe aus. Alle untersuchten Gletscher sind kleiner als 1.5 km2. Im Gegensatz zu dem ebenfalls sehr detaillierten Gletschermonitoring im Bereich der Rofenarche (Tirol), befindet sich das Sonnblickgebiet in einer sehr niederschlagsreichen Region. Dieser markante Unterschied in der Niederschlagsmenge hat eine deutlich höhere Klimasensitivität der Gletscher im Sonnblickgebiet zur Folge. Ein Vergleich der vorliegenden Ergebnisse für die 3 Gletscher des Monitorings im Bereich des Sonnblicks zeigt die große Bedeutung des Alpenhauptkammes als Klimascheide. So weist das nördlich gelegene Goldbergkees deutlich höhere Winterakkumulationen auf als die südlich gelegenen Gletscher Wurtenkees und Kleinfleißkees. Ergebnisse von kürzlich durchgeführten Messungen der Eismächtigkeiten zeigen für die untersuchten Gletscher maximale Eismächtigkeiten zwischen ca. 80 bis 150 m. Die vorliegenden Daten des Monitorings eignen sich sehr gut für die Kalibrierung and Validierung glazialhydrologische Modelle.

Annals of Glaciology, 2009

Global warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to ma... more Global warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to mass-balance investigation, the determination and monitoring of total glacial ice volume and ice-thickness distribution are important parameters for understanding the interactions between climate and the complex glacier system. Because of spatially irregular and sparse datasets, scaling of volume and ice-thickness distribution is often a challenging problem. This study focuses on two small (<2 km 2 ) temperate glaciers in the Hohe Tauern (Eastern Alps) region of central Austria. The period 2003-04 saw the first use of ground-penetrating radar (GPR) to determine the total ice volume and ice-thickness distribution of the two glaciers. A centre frequency of 20 MHz was used in point measuring mode. Despite variable data quality, bedrock reflections up to depths of >100 m were identified in the data. The acquired GPR data are irregularly distributed and the spatial density is too low to calculate reasonable bedrock topography with standard interpolation approaches. Thus one main focus of this study was to develop an appropriate interpolation technique. Eventually, kriging technique and a glacial mechanically based interpolation parameter were used. Mean calculated ice thicknesses for the two investigated glaciers are 40-50 m, with a maximum of 150-165 m. No direct validation data are available, so different considerations support the computed bedrock topography.

Annals of Glaciology, 2008

A detailed model of Alpine surface processes is used to simulate the amount of preferential depos... more A detailed model of Alpine surface processes is used to simulate the amount of preferential deposition as well as redistribution of snow due to snowdrift for two alpine glaciers (Goldbergkees and Kleinfleißkees, Austrian Alps). The sequence of snow-cover modelling consists of the simulation of the wind field with a mesoscale atmospheric model, a three-dimensional finite-element drift module, an energy-balance module and a snowpack module. All modules with the exception of the wind-field model are integrated within the Alpine3D model frame. The drift module of Alpine3D distinguishes between saltation and suspension and is able to capture preferential deposition of snow precipitation and redistribution of previously deposited snow. Validation of the simulated snow depth is done using the spatially dense snow-probing dataset collected during a campaign in May 2003. Simulated snow depths agree with measurements during winter 2002/03 at locations with detailed snow-height monitoring, taking into account the high spatial variability of snow depth on the glacier. Moreover, comparison of snow accumulation from model results with detailed probing on 1 May 2003 for the total glacier area shows that Alpine3D is able to capture major patterns of spatial distribution of snow accumulation. For the first time, the Alpine3D approach of using high-resolution wind fields from a meteorological model and a physical description of snow transport could be validated for a very steep glacierized area and for a full accumulation season. The results show that drift is a dominant factor to be considered for detailed glacier mass balances. Another dominant factor not considered in this study may be snow redistribution due to avalanches.

The paper describes the glaciohydrological monitoring in the region of Rauriser Sonnblick, which ... more The paper describes the glaciohydrological monitoring in the region of Rauriser Sonnblick, which is charcterised by long-term, comprehensive measurements of the glacier mass balance, the glacial discharge and the spatial distribution of precipitation and snow height. All investigated glaciers are less than 1.5 km2 in size. Annual precipitation in the Sonnblick region is high compared to another well established glacier monitoring in Austria (Rofenarche region, Tyrol). Thus climate sensitivity of glaciers in the Sonnblick region is much higher compared to the Rofenarche area. The analysis of available monitoring data from Sonnblick region reveals the high significance of the Alpine crest as a distinct climate divide. Consequently, winter accumulation is much more pronounced at Goldbergkees (north of the Alpine crest) compared to the Wurtenkees or Fleißkees which are situated south of the Alpine crest. Results from recently performed ice thickness measurements show values between approximate 80 to 150 m maximum ice thickness. The today status of the glacier monitoring in the Sonnblick-region is especially valuable for the calibration and validation of glaciohydrological models. In diesem Beitrag wird das glazialhydrologische Monitoring im Bereich der Rauriser Arche (Rauriser Sonnblick) beschrieben. Das Monitoring zeichnet sich durch langjährige und umfangreiche Messungen der Gletschermassenbilanz, des Glazialabflusses und der räumlich verteilten Niederschlagmenge und der Schneehöhe aus. Alle untersuchten Gletscher sind kleiner als 1.5 km2. Im Gegensatz zu dem ebenfalls sehr detaillierten Gletschermonitoring im Bereich der Rofenarche (Tirol), befindet sich das Sonnblickgebiet in einer sehr niederschlagsreichen Region. Dieser markante Unterschied in der Niederschlagsmenge hat eine deutlich höhere Klimasensitivität der Gletscher im Sonnblickgebiet zur Folge. Ein Vergleich der vorliegenden Ergebnisse für die 3 Gletscher des Monitorings im Bereich des Sonnblicks zeigt die große Bedeutung des Alpenhauptkammes als Klimascheide. So weist das nördlich gelegene Goldbergkees deutlich höhere Winterakkumulationen auf als die südlich gelegenen Gletscher Wurtenkees und Kleinfleißkees. Ergebnisse von kürzlich durchgeführten Messungen der Eismächtigkeiten zeigen für die untersuchten Gletscher maximale Eismächtigkeiten zwischen ca. 80 bis 150 m. Die vorliegenden Daten des Monitorings eignen sich sehr gut für die Kalibrierung and Validierung glazialhydrologische Modelle.

Global warming and glacier retreat are affecting the morphodynamics of proglacial rivers. In resp... more Global warming and glacier retreat are affecting the morphodynamics of proglacial rivers. In response to changing hydrology, their altered hydraulics will significantly impact future glacifluvial erosion and proglacial channel development. This study analysis proglacial channel evolution processes at the foreland of Austria's biggest glacier Pasterze by predicted runoff until 2050. A high-resolution digital elevation model was created by an unmanned aerial vehicle, channel bathymetry was sampled, a one-dimensional hydrodynamic-numerical model was generated, and bedload transport formulas were used to calculate the predicted transport capacity of the proglacial river. Due to the fine sediment composition near the glacier terminus (d 50 < 49.6 mm), the calculation results underline the process of headward erosion in the still unaffected, recently deglaciated river section. In contrast, an armor layer is already partly established by the coarse grain size distribution in the already incised river section (d 50 > 201 mm). Furthermore, already reoccurring exposed non-fluvial grain sizes combined with decreasing flow competence in the long term are indicators for erosion-resistant pavement layer formation and landform decoupling in the vertical direction. The presented study clearly shows that subsystems of 'developed channels' exhibiting pavement formation of non-fluvial deposits are found at the investigated glacier foreland. Thus, an extension accompanied by a refinement of the fluvial system in the sediment cascade approach was developed as a central result.

A third glacier inventory (GI3) is presented for the province of Salzburg where 173 glaciers are ... more A third glacier inventory (GI3) is presented for the province of Salzburg where 173 glaciers are located in the seven mountain ranges: Ankogel (47°4'N, 13°14'E), Glockner, Granatspitz, Sonnblick (Goldberg), Hochkönig, Venediger and Zillertal (47°8'N, 12°7'E). The basis for the new GI3 are orthophotos of 2007 and 2009 and the digital elevation model (DEM) of the southern part of Salzburg. On the basis of former inventories, area- and volume changes have been calculated. The biggest relative loss of glacier area per mountain range was found in the Ankogel range and on Hochkönig as a result of the disrupted structure of their small and thin glaciers. In terms of absolute values, the largest changes took place in the Glockner- and Venediger range with an area loss of -10.1 km**2 and -9.7 km**2 during the period between GI1 (1969) and GI3 (2007/2009), respectively. Volume changes have been calculated for nearly half of the glacier area in Salzburg, where DEMs were available. The Glockner, Granatspitz and Sonnblick mountain ranges showed a volume loss of -0.481 km**3 which corresponds to a mean thickness change of -10.5 m. An extrapolation of these changes to all of the 173 glaciers in Salzburg results in a loss of about 1.04 km**3 between GI1 and GI3 and 0.44 km**3 between GI2 and GI3. Overall annual changes in the province of Salzburg between GI2 and GI3 were higher than between GI1 and GI2 and show likewise changes such as those of Tyrol.

eco.mont (Journal on Protected Mountain Areas Research), 2014

Glaciers are important and fast changing landscape elements in Hohe Tauern National Park (HTNP). ... more Glaciers are important and fast changing landscape elements in Hohe Tauern National Park (HTNP). In 1998, 10% of the HTNP area was covered with ice, less than half of the glaciated area during the Little Ice Age maximum. Glaciological monitoring includes mass balance measurements, glacier inventories, length change records and flow velocity measurements, complemented by climatological, hydrological and dendrochronological observations. All these data evidence the climate and glacier history of HTNP in an outstanding way, comparable to few other sites in the world.

The Cryosphere, 2013

Glacier-wide mass balance has been measured for more than sixty years and is widely used as an in... more Glacier-wide mass balance has been measured for more than sixty years and is widely used as an indicator of climate change and to assess the glacier contribution to runoff and sea level rise. Until recently, comprehensive uncertainty assessments have rarely been carried out and mass balance data have often been applied using rough error estimation or without consideration of errors. In this study, we propose a framework for reanalysing glacier mass balance series that includes conceptual and statistical toolsets for assessment of random and systematic errors, as well as for validation and calibration (if necessary) of the glaciological with the geodetic balance results. We demonstrate the usefulness and limitations of the proposed scheme, drawing on an analysis that comprises over 50 recording periods for a dozen glaciers, and we make recommendations to investigators and users of glacier mass balance data. Reanalysing glacier mass balance series needs to become a standard procedure for every monitoring programme to improve data quality, including reliable uncertainty estimates.

EGU General Assembly Conference Abstracts, Apr 1, 2018

Annals of Glaciology, 2009

Global warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to ma... more Global warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to mass-balance investigation, the determination and monitoring of total glacial ice volume and ice-thickness distribution are important parameters for understanding the interactions between climate and the complex glacier system. Because of spatially irregular and sparse datasets, scaling of volume and ice-thickness distribution is often a challenging problem. This study focuses on two small (<2 km 2 ) temperate glaciers in the Hohe Tauern (Eastern Alps) region of central Austria. The period 2003-04 saw the first use of ground-penetrating radar (GPR) to determine the total ice volume and ice-thickness distribution of the two glaciers. A centre frequency of 20 MHz was used in point measuring mode. Despite variable data quality, bedrock reflections up to depths of >100 m were identified in the data. The acquired GPR data are irregularly distributed and the spatial density is too low to calculate reasonable bedrock topography with standard interpolation approaches. Thus one main focus of this study was to develop an appropriate interpolation technique. Eventually, kriging technique and a glacial mechanically based interpolation parameter were used. Mean calculated ice thicknesses for the two investigated glaciers are 40-50 m, with a maximum of 150-165 m. No direct validation data are available, so different considerations support the computed bedrock topography.

Annals of Glaciology, 2008

A detailed model of Alpine surface processes is used to simulate the amount of preferential depos... more A detailed model of Alpine surface processes is used to simulate the amount of preferential deposition as well as redistribution of snow due to snowdrift for two alpine glaciers (Goldbergkees and Kleinfleißkees, Austrian Alps). The sequence of snow-cover modelling consists of the simulation of the wind field with a mesoscale atmospheric model, a three-dimensional finite-element drift module, an energy-balance module and a snowpack module. All modules with the exception of the wind-field model are integrated within the Alpine3D model frame. The drift module of Alpine3D distinguishes between saltation and suspension and is able to capture preferential deposition of snow precipitation and redistribution of previously deposited snow. Validation of the simulated snow depth is done using the spatially dense snow-probing dataset collected during a campaign in May 2003. Simulated snow depths agree with measurements during winter 2002/03 at locations with detailed snow-height monitoring, taking into account the high spatial variability of snow depth on the glacier. Moreover, comparison of snow accumulation from model results with detailed probing on 1 May 2003 for the total glacier area shows that Alpine3D is able to capture major patterns of spatial distribution of snow accumulation. For the first time, the Alpine3D approach of using high-resolution wind fields from a meteorological model and a physical description of snow transport could be validated for a very steep glacierized area and for a full accumulation season. The results show that drift is a dominant factor to be considered for detailed glacier mass balances. Another dominant factor not considered in this study may be snow redistribution due to avalanches.

The paper describes the glaciohydrological monitoring in the region of Rauriser Sonnblick, which ... more The paper describes the glaciohydrological monitoring in the region of Rauriser Sonnblick, which is charcterised by long-term, comprehensive measurements of the glacier mass balance, the glacial discharge and the spatial distribution of precipitation and snow height. All investigated glaciers are less than 1.5 km2 in size. Annual precipitation in the Sonnblick region is high compared to another well established glacier monitoring in Austria (Rofenarche region, Tyrol). Thus climate sensitivity of glaciers in the Sonnblick region is much higher compared to the Rofenarche area. The analysis of available monitoring data from Sonnblick region reveals the high significance of the Alpine crest as a distinct climate divide. Consequently, winter accumulation is much more pronounced at Goldbergkees (north of the Alpine crest) compared to the Wurtenkees or Fleißkees which are situated south of the Alpine crest. Results from recently performed ice thickness measurements show values between approximate 80 to 150 m maximum ice thickness. The today status of the glacier monitoring in the Sonnblick-region is especially valuable for the calibration and validation of glaciohydrological models. In diesem Beitrag wird das glazialhydrologische Monitoring im Bereich der Rauriser Arche (Rauriser Sonnblick) beschrieben. Das Monitoring zeichnet sich durch langjährige und umfangreiche Messungen der Gletschermassenbilanz, des Glazialabflusses und der räumlich verteilten Niederschlagmenge und der Schneehöhe aus. Alle untersuchten Gletscher sind kleiner als 1.5 km2. Im Gegensatz zu dem ebenfalls sehr detaillierten Gletschermonitoring im Bereich der Rofenarche (Tirol), befindet sich das Sonnblickgebiet in einer sehr niederschlagsreichen Region. Dieser markante Unterschied in der Niederschlagsmenge hat eine deutlich höhere Klimasensitivität der Gletscher im Sonnblickgebiet zur Folge. Ein Vergleich der vorliegenden Ergebnisse für die 3 Gletscher des Monitorings im Bereich des Sonnblicks zeigt die große Bedeutung des Alpenhauptkammes als Klimascheide. So weist das nördlich gelegene Goldbergkees deutlich höhere Winterakkumulationen auf als die südlich gelegenen Gletscher Wurtenkees und Kleinfleißkees. Ergebnisse von kürzlich durchgeführten Messungen der Eismächtigkeiten zeigen für die untersuchten Gletscher maximale Eismächtigkeiten zwischen ca. 80 bis 150 m. Die vorliegenden Daten des Monitorings eignen sich sehr gut für die Kalibrierung and Validierung glazialhydrologische Modelle.

Annals of Glaciology, 2009

Global warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to ma... more Global warming is causing an apparent rapid retreat of many glaciers worldwide. In addition to mass-balance investigation, the determination and monitoring of total glacial ice volume and ice-thickness distribution are important parameters for understanding the interactions between climate and the complex glacier system. Because of spatially irregular and sparse datasets, scaling of volume and ice-thickness distribution is often a challenging problem. This study focuses on two small (<2 km 2 ) temperate glaciers in the Hohe Tauern (Eastern Alps) region of central Austria. The period 2003-04 saw the first use of ground-penetrating radar (GPR) to determine the total ice volume and ice-thickness distribution of the two glaciers. A centre frequency of 20 MHz was used in point measuring mode. Despite variable data quality, bedrock reflections up to depths of >100 m were identified in the data. The acquired GPR data are irregularly distributed and the spatial density is too low to calculate reasonable bedrock topography with standard interpolation approaches. Thus one main focus of this study was to develop an appropriate interpolation technique. Eventually, kriging technique and a glacial mechanically based interpolation parameter were used. Mean calculated ice thicknesses for the two investigated glaciers are 40-50 m, with a maximum of 150-165 m. No direct validation data are available, so different considerations support the computed bedrock topography.

Annals of Glaciology, 2008

A detailed model of Alpine surface processes is used to simulate the amount of preferential depos... more A detailed model of Alpine surface processes is used to simulate the amount of preferential deposition as well as redistribution of snow due to snowdrift for two alpine glaciers (Goldbergkees and Kleinfleißkees, Austrian Alps). The sequence of snow-cover modelling consists of the simulation of the wind field with a mesoscale atmospheric model, a three-dimensional finite-element drift module, an energy-balance module and a snowpack module. All modules with the exception of the wind-field model are integrated within the Alpine3D model frame. The drift module of Alpine3D distinguishes between saltation and suspension and is able to capture preferential deposition of snow precipitation and redistribution of previously deposited snow. Validation of the simulated snow depth is done using the spatially dense snow-probing dataset collected during a campaign in May 2003. Simulated snow depths agree with measurements during winter 2002/03 at locations with detailed snow-height monitoring, taking into account the high spatial variability of snow depth on the glacier. Moreover, comparison of snow accumulation from model results with detailed probing on 1 May 2003 for the total glacier area shows that Alpine3D is able to capture major patterns of spatial distribution of snow accumulation. For the first time, the Alpine3D approach of using high-resolution wind fields from a meteorological model and a physical description of snow transport could be validated for a very steep glacierized area and for a full accumulation season. The results show that drift is a dominant factor to be considered for detailed glacier mass balances. Another dominant factor not considered in this study may be snow redistribution due to avalanches.

The paper describes the glaciohydrological monitoring in the region of Rauriser Sonnblick, which ... more The paper describes the glaciohydrological monitoring in the region of Rauriser Sonnblick, which is charcterised by long-term, comprehensive measurements of the glacier mass balance, the glacial discharge and the spatial distribution of precipitation and snow height. All investigated glaciers are less than 1.5 km2 in size. Annual precipitation in the Sonnblick region is high compared to another well established glacier monitoring in Austria (Rofenarche region, Tyrol). Thus climate sensitivity of glaciers in the Sonnblick region is much higher compared to the Rofenarche area. The analysis of available monitoring data from Sonnblick region reveals the high significance of the Alpine crest as a distinct climate divide. Consequently, winter accumulation is much more pronounced at Goldbergkees (north of the Alpine crest) compared to the Wurtenkees or Fleißkees which are situated south of the Alpine crest. Results from recently performed ice thickness measurements show values between approximate 80 to 150 m maximum ice thickness. The today status of the glacier monitoring in the Sonnblick-region is especially valuable for the calibration and validation of glaciohydrological models. In diesem Beitrag wird das glazialhydrologische Monitoring im Bereich der Rauriser Arche (Rauriser Sonnblick) beschrieben. Das Monitoring zeichnet sich durch langjährige und umfangreiche Messungen der Gletschermassenbilanz, des Glazialabflusses und der räumlich verteilten Niederschlagmenge und der Schneehöhe aus. Alle untersuchten Gletscher sind kleiner als 1.5 km2. Im Gegensatz zu dem ebenfalls sehr detaillierten Gletschermonitoring im Bereich der Rofenarche (Tirol), befindet sich das Sonnblickgebiet in einer sehr niederschlagsreichen Region. Dieser markante Unterschied in der Niederschlagsmenge hat eine deutlich höhere Klimasensitivität der Gletscher im Sonnblickgebiet zur Folge. Ein Vergleich der vorliegenden Ergebnisse für die 3 Gletscher des Monitorings im Bereich des Sonnblicks zeigt die große Bedeutung des Alpenhauptkammes als Klimascheide. So weist das nördlich gelegene Goldbergkees deutlich höhere Winterakkumulationen auf als die südlich gelegenen Gletscher Wurtenkees und Kleinfleißkees. Ergebnisse von kürzlich durchgeführten Messungen der Eismächtigkeiten zeigen für die untersuchten Gletscher maximale Eismächtigkeiten zwischen ca. 80 bis 150 m. Die vorliegenden Daten des Monitorings eignen sich sehr gut für die Kalibrierung and Validierung glazialhydrologische Modelle.