Reconstruction of the annual balance of Vadret da Morteratsch, Switzerland, since 1865

Nemec, Johanna; Huybrechts, Philippe; Rybak, Oleg; Oerlemans, J.

doi:10.3189/172756409787769609

Cited by 43 publications

(48 citation statements)

References 21 publications

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“…Radic and Hock, 2006). As Nemec et al (2009) have shown in a transient model run (1865 to 2005) for Morteratsch Glacier, the mass balance for a fixed geometry was about 46% more negative than the hydrological one, which is in good agreement with the results obtained here.…”

Section: Implications For Mass Balance Reconstructionssupporting

confidence: 81%

The influence of changes in glacier extent and surface elevation on modeled mass balance

Paul

2010

The Cryosphere

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Abstract. Glaciers are widely recognized as unique demonstration objects for climate change impacts, mostly due to the strong change of glacier length in response to small climatic changes. However, glacier mass balance as the direct response to the annual atmospheric conditions can be better interpreted in meteorological terms. When the climatic signal is deduced from long-term mass balance data, changes in glacier geometry (i.e. surface extent and elevation) must be considered as such adjustments form an essential part of the glacier reaction to new climatic conditions. In this study, a set of modelling experiments is performed to assess the influence of changes in glacier geometry on mass balance for constant climatic conditions. The calculations are based on a simplified distributed energy/mass balance model in combination with information on glacier extent and surface elevation for the years 1850 and 1973/1985 for about 60 glaciers in the Swiss Alps. The results reveal that over this period about 50-70% of the glacier reaction to climate change (here a one degree increase in temperature) is "hidden" in the geometric adjustment, while only 30-50% can be measured as the long-term mean mass balance. For larger glaciers, the effect of the areal change is partly reduced by a lowered surface elevation, which results in a slightly more negative balance despite a potential increase of topographic shading. In view of several additional reinforcement feedbacks that are observed in periods of strong glacier decline, it seems that the climatic interpretation of long-term mass balance data is rather complex.

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Section: Implications For Mass Balance Reconstructionssupporting

confidence: 81%

The influence of changes in glacier extent and surface elevation on modeled mass balance

Paul

2010

The Cryosphere

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“…Morteratsch is a large valley glacier with an altitude that spans from 2030 to 3976 m a.s.l., with an area of 15.81 km 2 . It is a typical north-facing Alpine glacier experiencing negative mass balances in the last century (Nemec et al, 2009;Oerlemans et al, 2009;WGMS, 2017). The glacier apparatus is constituted by the Morteratsch Glacier and its tributary, the Pers Glacier.…”

Section: Study Areamentioning

confidence: 99%

Impact of impurities and cryoconite on the optical properties of the Morteratsch Glacier (Swiss Alps)

et al. 2017

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Abstract. The amount of reflected energy by snow and ice plays a fundamental role in their melting processes. Different non-ice materials (carbonaceous particles, mineral dust (MD), microorganisms, algae, etc.) can decrease the reflectance of snow and ice promoting the melt. The object of this paper is to assess the capability of field and satellite (EO-1 Hyperion) hyperspectral data to characterize the impact of light-absorbing impurities (LAIs) on the surface reflectance of ice and snow of the Vadret da Morteratsch, a large valley glacier in the Swiss Alps. The spatial distribution of both narrow-band and broad-band indices derived from Hyperion was analyzed in relation to ice and snow impurities. In situ and laboratory reflectance spectra were acquired to characterize the optical properties of ice and cryoconite samples. The concentrations of elemental carbon (EC), organic carbon (OC) and levoglucosan were also determined to characterize the impurities found in cryoconite. Multi-wavelength absorbance spectra were measured to compare the optical properties of cryoconite samples and local moraine sediments. In situ reflectance spectra showed that the presence of impurities reduced ice reflectance in visible wavelengths by 80-90 %. Satellite data also showed the outcropping of dust during the melting season in the upper parts of the glacier, revealing that seasonal input of atmospheric dust can decrease the reflectance also in the accumulation zone of the glacier. The presence of EC and OC in cryoconite samples suggests a relevant role of carbonaceous and organic material in the darkening of the ablation zone. This darkening effect is added to that caused by fine debris from lateral moraines, which is assumed to represent a large fraction of cryoconite. Possible input of anthropogenic activity cannot be excluded and further research is needed to assess the role of human activities in the darkening process of glaciers observed in recent years.

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“…Spatially, albedo values are typically assumed as constant for the calculation of glacier surface mass balances (Gabbi, Carenzo, Pellicciotti, Bauder, & Funk, 2014;Machguth et al, 2006;Nemec, Huybrechts, Rybak, & Oerlemans, 2009;Pellicciotti et al, 2005). However, albedo is known to be a crucial parameter for glacier ablation (e.g.…”

Section: Distributed Mass Balance Modellingmentioning

confidence: 99%

Imaging spectroscopy to assess the composition of ice surface materials and their impact on glacier mass balance

Naegeli

Damm

Huss

et al. 2015

Remote Sensing of Environment

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Glacier surfaces are not only composed of ice or snow but are heterogeneous mixtures of different materials. The occurrence and dynamics of light-absorbing impurities affect ice surface characteristics and strongly influence glacier melt processes. However, our understanding of the spatial distribution of impurities and their impact on ice surface characteristics and the glacier's energy budget is still limited. We use imaging spectroscopy in combination with in-situ experiments to assess the composition of ice surface materials and their respective impact on surface albedo and glacier melt rates. Spectroscopy data were acquired in August 2013 using the Airborne Prism EXperiment (APEX) imaging spectrometer and were used to map the abundances of six predominant surface materials on Glacier de la Plaine Morte, Swiss Alps. A pixel-based classification revealed that about 10% of the ice surface is covered with snow, water or debris. The remaining 90% of the surface can be divided into three types of glacier ice, namely~7% dirty ice,~43% pure ice and~39% bright ice. Spatially distributed spectral albedo derived from APEX reflectance data in combination with in-situ multi-angular spectroscopic measurements was used to analyse albedo patterns present on the glacier surface. About 85% of all pixels exhibit a low albedo between 0.1 and 0.4 (mean albedo 0.29 ± 0.12), indicating that Glacier de la Plaine Morte is covered with a significant amount of light-absorbing impurities, resulting in a strong ice-albedo feedback during the ablation season. Using a pixel-based albedo map instead of a constant albedo for ice (0.34) as input for a mass balance model revealed that the glacier-wide total ablation remained similar (10% difference). However, the large local variations in mass balance can only be reproduced using the pixel-based albedo derived from APEX, emphasizing the need to quantify spatial albedo differences as an important input for glacier mass balance models.

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Reconstruction of the annual balance of Vadret da Morteratsch, Switzerland, since 1865

Cited by 43 publications

References 21 publications

The influence of changes in glacier extent and surface elevation on modeled mass balance

The influence of changes in glacier extent and surface elevation on modeled mass balance

Impact of impurities and cryoconite on the optical properties of the Morteratsch Glacier (Swiss Alps)

Imaging spectroscopy to assess the composition of ice surface materials and their impact on glacier mass balance

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