scholarly journals Historical glacier outlines from digitized topographic maps of the Swiss Alps

2018 ◽  
Vol 10 (2) ◽  
pp. 805-814 ◽  
Author(s):  
Daphné Freudiger ◽  
David Mennekes ◽  
Jan Seibert ◽  
Markus Weiler
Keyword(s):  
Large Scale ◽  
Swiss Alps ◽  
Ice Age ◽  
Aerial Photographs ◽  
Topographic Maps ◽  
Glacier Mass Balance ◽  
European Alps ◽  
Glacier Area ◽  
Basin Scale

Abstract. Since the end of the Little Ice Age around 1850, the total glacier area of the central European Alps has considerably decreased. In order to understand the changes in glacier coverage at various scales and to model past and future streamflow accurately, long-term and large-scale datasets of glacier outlines are needed. To fill the gap between the morphologically reconstructed glacier outlines from the moraine extent corresponding to the time period around 1850 and the first complete dataset of glacier areas in the Swiss Alps from aerial photographs in 1973, glacier areas from 80 sheets of a historical topographic map (the Siegfried map) were manually digitized for the publication years 1878–1918 (further called first period, with most sheets being published around 1900) and 1917–1944 (further called second period, with most sheets being published around 1935). The accuracy of the digitized glacier areas was then assessed through a two-step validation process: the data were (1) visually and (2) quantitatively compared to glacier area datasets of the years 1850, 1973, 2003, and 2010, which were derived from different sources, at the large scale, basin scale, and locally. The validation showed that at least 70 % of the digitized glaciers were comparable to the outlines from the other datasets and were therefore plausible. Furthermore, the inaccuracy of the manual digitization was found to be less than 5 %. The presented datasets of glacier outlines for the first and second periods are a valuable source of information for long-term glacier mass balance or hydrological modelling in glacierized basins. The uncertainty of the historical topographic maps should be considered during the interpretation of the results. The datasets can be downloaded from the FreiDok plus data repository (https://freidok.uni-freiburg.de/data/15008, https://doi.org/10.6094/UNIFR/15008).

scholarly journals Historical glacier outlines from digitized topographic maps of the Swiss Alps

2017 ◽  
Author(s):  
Daphné Freudiger ◽  
David Mennekes ◽  
Jan Seibert ◽  
Markus Weiler
Keyword(s):  
Large Scale ◽  
Swiss Alps ◽  
Ice Age ◽  
Aerial Photographs ◽  
Topographic Maps ◽  
Data Repository ◽  
Glacier Mass Balance ◽  
European Alps ◽  
Glacier Area

Abstract. Since the end of the Little Ice Age around 1850, the total glacier area of the Central European Alps has considerably decreased. In order to understand the changes in glacier coverage at various scales and to model past and future streamflow accurately, long-term and large-scale datasets of glacier outlines are needed. To fill the gap between the morphologically reconstructed glacier outlines from the moraine extent corresponding to the time period around 1850 and the first complete dataset of glacier areas in the Swiss Alps from aerial photographs in 1973, glacier area from 80 sheets of a historical topographic map, so-called Siegfried map, were manually digitized for the publication years 1878–1918 (further called first period, with most sheets being published around 1900) and 1917–1944 (further called second period, with most sheets being published around 1935). The accuracy of the digitized glacier areas was then assessed through a two-step validation process: the data was (1) visually and (2) quantitatively compared to glacier area datasets of the years 1850, 1973, 2003, and 2010, which were derived from different sources. The validation showed that at least 70 % of the digitized glaciers were comparable to the outlines from the other datasets and were therefore plausible. Furthermore, the accuracy of the manual digitization was found to be lower than 5 %. The presented datasets of glacier outlines for the first and second periods were found to be valuable source of information for long-term glacier mass balance or hydrological modelling in glacierized basins if the uncertainty of the historical topographic maps is considered in the interpretation of the results. The datasets can be downloaded from the FreiDok plus data repository (https://freidok.uni-freiburg.de/data/12874, https://doi.org/10.6094/UNIFR/12874).

Species Responses to Grazing and Environmental-Factors in an Arid Halophytic Shrubland Community

1987 ◽  
Vol 35 (2) ◽  
pp. 135 ◽  
Author(s):  
RB Hacker
Keyword(s):  
Environmental Factors ◽  
Soil Salinity ◽  
Large Scale ◽  
Chemical Properties ◽  
Grazing Pressure ◽  
Aerial Photographs ◽  
Small Scale ◽  
Factors Affecting ◽  
Species Responses

Species responses to grazing and environmental factors were studied in an arid halophytic shrubland community in Western Australia. The grazing responses of major shrub species were defined by using reciprocal averaging ordination of botanical data, interpreted in conjunction with a similar ordination of soil chemical properties and measures of soil erosion derived from large-scale aerial photographs. An apparent small-scale interaction between grazing and soil salinity was also defined. Long-term grazing pressure is apparently reduced on localised areas of high salinity. Environmental factors affecting species distribution are complex and appear to include soil salinity, soil cationic balance, geomorphological variation and the influence of cryptogamic crusts on seedling establishment.

scholarly journals Semi-automated calibration method for modelling of mountain permafrost evolution in Switzerland

2016 ◽  
Vol 10 (6) ◽  
pp. 2693-2719 ◽  
Author(s):  
Antoine Marmy ◽  
Jan Rajczak ◽  
Reynald Delaloye ◽  
Christin Hilbich ◽  
Martin Hoelzle ◽  
...  
Keyword(s):  
Large Scale ◽  
Calibration Method ◽  
Swiss Alps ◽  
Climate Projections ◽  
European Alps ◽  
Permafrost Degradation ◽  
Future Evolution ◽  
Mountainous Regions ◽  
Automated Calibration ◽  
The Future

Abstract. Permafrost is a widespread phenomenon in mountainous regions of the world such as the European Alps. Many important topics such as the future evolution of permafrost related to climate change and the detection of permafrost related to potential natural hazards sites are of major concern to our society. Numerical permafrost models are the only tools which allow for the projection of the future evolution of permafrost. Due to the complexity of the processes involved and the heterogeneity of Alpine terrain, models must be carefully calibrated, and results should be compared with observations at the site (borehole) scale. However, for large-scale applications, a site-specific model calibration for a multitude of grid points would be very time-consuming. To tackle this issue, this study presents a semi-automated calibration method using the Generalized Likelihood Uncertainty Estimation (GLUE) as implemented in a 1-D soil model (CoupModel) and applies it to six permafrost sites in the Swiss Alps. We show that this semi-automated calibration method is able to accurately reproduce the main thermal condition characteristics with some limitations at sites with unique conditions such as 3-D air or water circulation, which have to be calibrated manually. The calibration obtained was used for global and regional climate model (GCM/RCM)-based long-term climate projections under the A1B climate scenario (EU-ENSEMBLES project) specifically downscaled at each borehole site. The projection shows general permafrost degradation with thawing at 10 m, even partially reaching 20 m depth by the end of the century, but with different timing among the sites and with partly considerable uncertainties due to the spread of the applied climatic forcing.

scholarly journals The impact of Saharan dust and black carbon on albedo and long-term glacier mass balance

2015 ◽  
Vol 9 (1) ◽  
pp. 1133-1175 ◽  
Author(s):  
J. Gabbi ◽  
M. Huss ◽  
A. Bauder ◽  
F. Cao ◽  
M. Schwikowski
Keyword(s):  
Mass Balance ◽  
Black Carbon ◽  
Mineral Dust ◽  
Ice Cores ◽  
Swiss Alps ◽  
Saharan Dust ◽  
Glacier Mass Balance ◽  
Mass Balances ◽  
The Impact

Abstract. Light-absorbing impurities in snow and ice control glacier melt as shortwave radiation represents the main component of the surface energy balance. Here, we investigate the long-term effect of snow impurities, i.e. Saharan dust and black carbon (BC), on albedo and glacier mass balance. The analysis was performed over the period 1914–2014 for two sites on Claridenfirn, Swiss Alps, where an outstanding 100 year record of seasonal mass balance measurements is available. Information on atmospheric deposition of mineral dust and BC over the last century was retrieved from two firn/ice cores of high-alpine sites. A combined mass balance and snow/firn layer model was employed to assess the dust/BC-albedo feedback. Compared to pure snow conditions, the presence of Saharan dust and BC lowered the mean annual albedo by 0.04–0.06 and increased melt by 15–19% on average depending on the location on the glacier. BC clearly dominated absorption which is about three times higher than that of mineral dust. The upper site has experienced mainly positive mass balances and impurity layers were continuously buried whereas at the lower site, surface albedo was more strongly influenced by re-exposure of dust-enriched layers due to frequent years with negative mass balances.

scholarly journals Uncertainty in Historical Land-Use Reconstructions with Topographic Maps

2014 ◽  
Vol 33 (3) ◽  
pp. 55-63 ◽  
Author(s):  
Dominik Kaim ◽  
Jacek Kozak ◽  
Krzysztof Ostafin ◽  
Monika Dobosz ◽  
Katarzyna Ostapowicz ◽  
...  
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Reliability Assessment ◽  
Swiss Alps ◽  
Topographic Maps ◽  
Forest Cover Change ◽  
Change Analysis ◽  
Polish Carpathians ◽  
Historical Land Use

Abstract The paper presents the outcomes of the uncertainty investigation of a long-term forest cover change analysis in the Polish Carpathians (nearly 20,000 km2) and Swiss Alps (nearly 10,000 km2) based on topographic maps. Following Leyk et al. (2005) all possible uncertainties are grouped into three domains - production-oriented, transformation- oriented and application-oriented. We show typical examples for each uncertainty domain, encountered during the forest cover change analysis and discuss consequences for change detection. Finally, a proposal for reliability assessment is presented.

scholarly journals Extrapolating glacier mass balance to the mountain-range scale: the European Alps 1900–2100

2012 ◽  
Vol 6 (4) ◽  
pp. 713-727 ◽  
Author(s):  
M. Huss
Keyword(s):  
Mass Balance ◽  
Multiple Regression ◽  
Volume Change ◽  
Data Series ◽  
Glacier Mass Balance ◽  
Mountain Range ◽  
European Alps ◽  
Ice Volume ◽  
Area Reduction

Abstract. This study addresses the extrapolation of in-situ glacier mass balance measurements to the mountain-range scale and aims at deriving time series of area-averaged mass balance and ice volume change for all glaciers in the European Alps for the period 1900–2100. Long-term mass balance series for 50 Swiss glaciers based on a combination of field data and modelling, and WGMS data for glaciers in Austria, France and Italy are used. A complete glacier inventory is available for the year 2003. Mass balance extrapolation is performed based on (1) arithmetic averaging, (2) glacier hypsometry, and (3) multiple regression. Given a sufficient number of data series, multiple regression with variables describing glacier geometry performs best in reproducing observed spatial mass balance variability. Future mass changes are calculated by driving a combined model for mass balance and glacier geometry with GCM ensembles based on four emission scenarios. Mean glacier mass balance in the European Alps is −0.31 ± 0.04 m w.e. a−1 in 1900–2011, and −1 m w.e. a−1 over the last decade. Total ice volume change since 1900 is −96 ± 13 km3; annual values vary between −5.9 km3 (1947) and +3.9 km3 (1977). Mean mass balances are expected to be around −1.3 m w.e. a−1 by 2050. Model results indicate a glacier area reduction of 4–18% relative to 2003 for the end of the 21st century.

scholarly journals Ice-volume changes of selected glaciers in the Swiss Alps since the end of the 19th century

2007 ◽  
Vol 46 ◽  
pp. 145-149 ◽  
Author(s):  
Andreas Bauder ◽  
Martin Funk ◽  
Matthias Huss
Keyword(s):  
19Th Century ◽  
Temporal Variations ◽  
Swiss Alps ◽  
Ice Age ◽  
Aerial Photographs ◽  
Volume Changes ◽  
Thickness Change ◽  
Ice Volume ◽  
The 1960S ◽  
The 19Th Century

AbstractThe evolution of surface topography of glaciers in the Swiss Alps is well documented with high-resolution aerial photographs repeatedly recorded since the 1960s and further back in time with topographic maps including elevation contour lines first surveyed in the mid-19th century. In order to quantify and interpret glacier changes in the Swiss Alps, time series of volume changes over the last 100–150 years have been collected. The available datasets provide a detailed spatial resolution for the retreat period since the end of the Little Ice Age. The spatial distribution as well as temporal variations of the thickness change were analyzed. A significant ice loss since the end of the 19th century was observed in the ablation area, while the changes in the accumulation area were small. We found moderate negative secular rates until the 1960s, followed by steady to positive rates for about two decades and strong ice loss starting in the 1980s which has lasted until the present. An evaluation of 19 glaciers revealed a total ice volume loss of about 13km3 since the 1870s, of which 8.7 km3 occurred since the 1920s and 3.5 km3 since 1980. Decadal mean net balance rates for the periods 1920–60, 1960–80 and 1980–present are –0.29, –0.03 and –0.53ma–1w.e., respectively.

scholarly journals New long-term mass-balance series for the Swiss Alps

2015 ◽  
Vol 61 (227) ◽  
pp. 551-562 ◽  
Author(s):  
Matthias Huss ◽  
Laurie Dhulst ◽  
Andreas Bauder
Keyword(s):  
Mass Balance ◽  
Spatial Interpolation ◽  
Swiss Alps ◽  
Continuous Series ◽  
European Alps ◽  
Ice Volume ◽  
Distributed Modelling ◽  
Direct Measurements ◽  
Annual Balance

AbstractIn this study we present 19 new or re-analysed series of glacier-wide seasonal mass balance for the Swiss Alps based on direct measurements. The records partly start around 1920 and continue until today. Previously unpublished and unevaluated observations of point winter and annual balance are compiled from various sources and archives. These highly valuable datasets have not yet been consistently evaluated and were thus unavailable to the scientific community. Using distributed modelling for spatial interpolation and extrapolation and homogenization of the point measurements, we infer continuous series of area-averaged mass balance. The results are validated against independent decadal ice volume changes from photogrammetric surveys. Six of the new seasonal series cover 60 years and more and add a substantial amount of information on the variations of regional glacier mass change. This will strengthen the worldwide collection of glacier monitoring data, especially for the data-sparse period before the 1980s. We compare our results to existing long-term series and present an updated assessment of mass-balance variability and glacier sensitivity throughout the European Alps.

scholarly journals Mass balance of Pizolgletscher

2010 ◽  
Vol 65 (2) ◽  
pp. 80-91 ◽  
Author(s):  
M. Huss
Keyword(s):  
Mass Balance ◽  
Swiss Alps ◽  
Aerial Photographs ◽  
Balance Model ◽  
New Approach ◽  
Ice Volume ◽  
North Eastern ◽  
First Results ◽  
Data Points

Abstract. Half of the glaciers in the Swiss Alps are smaller than 0.1 km2. Despite this, the mass budget of small glaciers and their response to ongoing climate change is rarely studied. A new mass balance monitoring programme on Pizolgletscher (0.08 km2) in north-eastern Switzerland was started in 2006. This paper presents first results and describes a new approach to determining the mass balance of glaciers. Seasonal field observations are interpreted using a distributed mass balance model in daily resolution that allows spatial inter- and extrapolation of sparse data points and the calculation of mass balance over arbitrary time periods. Evaluation of aerial photographs acquired in subdecadal intervals since 1968 allows inclusion of data on changes in glacier area and ice volume, contributing towards a long-term reconstruction of Pizolgletscher's mass balance. The analysis revealed fast mass loss over the last three years with annual balances of -1.61 m w.e. in 2006/2007, -0.71 m w.e. in 2007/2008, and -1.46 m w.e. in 2008/2009 and high spatial variability of mass balance on Pizolgletscher.

scholarly journals Temperature and mineral dust variability recorded in two low accumulation Alpine ice cores over the last millennium

2017 ◽  
Author(s):  
Pascal Bohleber ◽  
Tobias Erhardt ◽  
Nicole Spaulding ◽  
Helene Hoffmann ◽  
Hubertus Fischer ◽  
...  
Keyword(s):  
Time Series ◽  
Mineral Dust ◽  
Ice Core ◽  
Ice Cores ◽  
Temperature Reconstruction ◽  
Ice Age ◽  
European Alps ◽  
Annual Layer ◽  
Instrumental Temperature

Abstract. Among ice core drilling sites in the European Alps, the Colle Gnifetti (CG) glacier saddle is the only one to offer climate records back to at least 1000 years. This unique long-term archive is the result of an exceptionally low net accumulation driven by wind erosion and rapid annual layer thinning. To-date, however, the full exploitation of the CG time series has been hampered by considerable dating uncertainties and the seasonal summer bias in snow preservation. Using a new core drilled in 2013 we extend annual layer counting, for the first time at CG, over the last 1000 years and add additional constraints to the resulting age scale from radiocarbon dating. Based on this improved age scale, and using a multi-core approach with a neighboring ice core, we explore the potential for reconstructing long-term temperature variability from the stable water isotope and mineral dust proxy time series. A high and potentially non-stationary isotope/temperature sensitivity limits the quantitative use of the stable isotope variability thus far. However, we find substantial agreement comparing the mineral dust proxy Ca2+ with instrumental temperature. The temperature-related variability in the Ca2+ record is explained based on the temperature-dependent snow preservation bias combined with the advection of dust-rich air masses coinciding with warm temperatures. We show that using the Ca2+ trends for a quantitative temperature reconstruction results in good agreement with instrumental temperature and the latest summer temperature reconstruction derived from other archives covering the last 1000 years. This includes a Little Ice Age cold period as well as a medieval climate anomaly. In particular, part of the medieval climate period around 1100–1200 AD stands out through an increased occurrence of dust events, potentially resulting from a relative increase in meridional flow and dry conditions over the Mediterranean.

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