scholarly journals Recent Increases in Winter Snowfall Provide Resilience to Very Small Glaciers in the Julian Alps, Europe

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 263
Author(s):  
Renato R. Colucci ◽  
Manja Žebre ◽  
Csaba Zsolt Torma ◽  
Neil F. Glasser ◽  
Eleonora Maset ◽  
...  
Keyword(s):  
Mass Balance ◽  
Atlantic Multidecadal Oscillation ◽  
Snow Accumulation ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
European Alps ◽  
Positive Feedbacks ◽  
Winter Snow ◽  
Geodetic Mass Balance ◽  
The Impact

Very small glaciers (<0.5 km2) account for more than 80% of the total number of glaciers and more than 15% of the total glacier area in the European Alps. This study seeks to better understand the impact of extreme snowfall events on the resilience of very small glaciers and ice patches in the southeastern European Alps, an area with the highest mean annual precipitation in the entire Alpine chain. Mean annual precipitation here is up to 3300 mm water equivalent, and the winter snow accumulation is approximately 6.80 m at 1800 m asl averaged over the period 1979–2018. As a consequence, very small glaciers and ice/firn patches are still present in this area at rather low altitudes (1830–2340 m). We performed repeated geodetic mass balance measurements on 14 ice bodies during the period 2006–2018 and the results show an increase greater than 10% increase in ice volume over this period. This is in accordance with several extreme winter snow accumulations in the 2000s, promoting a positive mass balance in the following years. The long-term evolution of these very small glaciers and ice bodies matches well with changes in mean temperature of the ablation season linked to variability of Atlantic Multidecadal Oscillation. Nevertheless, the recent behaviour of such residual ice masses in this area where orographic precipitation represents an important component of weather amplification is somehow different to most of the Alps. We analysed synoptic meteorological conditions leading to the exceptional snowy winters in the 2000s, which appear to be related to the influence and modification of atmospheric planetary waves and Arctic Amplification, with further positive feedbacks due to change in local sea surface temperature and its interactions with low level flows and the orography. Although further summer warming is expected in the next decades, we conclude that modification of storm tracks and more frequent occurrence of extreme snowfall events during winter are crucial in ensuring the resilience of small glacial remnants in maritime alpine sectors.

scholarly journals MODELING PRECIPITATION DEPENDENT FOREST RESILIENCE IN INDIA

2018 ◽  
Vol XLII-3 ◽  
pp. 263-266 ◽  
Author(s):  
P. Das ◽  
M. D. Behera ◽  
P. S. Roy
Keyword(s):  
Forest Cover ◽  
Vegetation Type ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
High Tendency ◽  
North East India ◽  
North East ◽  
Forest Resilience ◽  
The Impact

The impact of long term climate change that imparts stress on forest could be perceived by studying the regime shift of forest ecosystem. With the change of significant precipitation, forest may go through density change around globe at different spatial and temporal scale. The 100 class high resolution (60 meter spatial resolution) Indian vegetation type map was used in this study recoded into four broad categories depending on phrenology as (i) forest, (ii) scrubland, (iii) grassland and (iv) treeless area. The percentage occupancy of forest, scrub, grass and treeless were observed as 19.9&amp;thinsp;%, 5.05&amp;thinsp;%, 1.89&amp;thinsp;% and 7.79&amp;thinsp;% respectively. Rest of the 65.37&amp;thinsp;% land area was occupied by the cropland, built-up, water body and snow covers. The majority forest cover were appended into a 5&amp;thinsp;km&amp;thinsp;&amp;times;&amp;thinsp;5&amp;thinsp;km grid, along with the mean annual precipitation taken from Bioclim data. The binary presence and absence of different vegetation categories in relates to the annual precipitation was analyzed to calculate their resilience expressed in probability values ranging from 0 to 1. Forest cover observed having resilience probability (Pr) &amp;lt;&amp;thinsp;0.3 in only 0.3&amp;thinsp;% (200&amp;thinsp;km<sup>2</sup>) of total forest cover in India, which was 4.3&amp;thinsp;% &amp;lt;&amp;thinsp;0.5&amp;thinsp;Pr. Majority of the scrubs and grass (64.92&amp;thinsp;% Pr&amp;thinsp;&amp;lt;&amp;thinsp;0.5) from North East India which were the shifting cultivation lands showing low resilience, having their high tendency to be transform to forest. These results have spatial explicitness to highlight the resilient and non-resilient distribution of forest, scrub and grass, and treeless areas in India.

scholarly journals Surface elevation and mass changes of all Swiss glaciers 1980–2010

2015 ◽  
Vol 9 (2) ◽  
pp. 525-540 ◽  
Author(s):  
M. Fischer ◽  
M. Huss ◽  
M. Hoelzle
Keyword(s):  
Mass Balance ◽  
Accuracy Assessment ◽  
Swiss Alps ◽  
Surface Elevation ◽  
European Alps ◽  
Volume Changes ◽  
Glacier Inventory ◽  
Digital Elevation ◽  
Source Data ◽  
Geodetic Mass Balance

Abstract. Since the mid-1980s, glaciers in the European Alps have shown widespread and accelerating mass losses. This article presents glacier-specific changes in surface elevation, volume and mass balance for all glaciers in the Swiss Alps from 1980 to 2010. Together with glacier outlines from the 1973 inventory, the DHM25 Level 1 digital elevation models (DEMs) for which the source data over glacierized areas were acquired from 1961 to 1991 are compared to the swissALTI3D DEMs from 2008 to 2011 combined with the new Swiss Glacier Inventory SGI2010. Due to the significant differences in acquisition dates of the source data used, mass changes are temporally homogenized to directly compare individual glaciers or glacierized catchments. Along with an in-depth accuracy assessment, results are validated against volume changes from independent photogrammetrically derived DEMs of single glaciers. Observed volume changes are largest between 2700 and 2800 m a.s.l. and remarkable even above 3500 m a.s.l. The mean geodetic mass balance is −0.62 ± 0.07 m w.e. yr−1 for the entire Swiss Alps over the reference period 1980–2010. For the main hydrological catchments, it ranges from −0.52 to −1.07 m w.e. yr−1. The overall volume loss calculated from the DEM differencing is −22.51 ± 1.76 km3.

scholarly journals Using ground-penetrating radar to image previous years’ summer surfaces for mass-balance measurements

1997 ◽  
Vol 24 ◽  
pp. 355-360 ◽  
Author(s):  
Jack Kohler ◽  
John Moore ◽  
Mike Kennett ◽  
Rune Engeset ◽  
Hallgeir Elvehøy
Keyword(s):  
Dielectric Properties ◽  
Mass Balance ◽  
Ground Penetrating Radar ◽  
Radar Data ◽  
Snow Accumulation ◽  
Ice Surface ◽  
Winter Snow ◽  
Depth Scale ◽  
Ground Penetrating ◽  
Previous Summer

In traditional mass-balance measurements one estimates winter snow accumulation by identifying the depth to the previous summer’s snow or ice surface using a snow probe. This is labor-intensive and unreliable for inhomogeneous summer surfaces. Another method is to image internal reflection horizons using a ground-penetrating radar (GPR), which has advantages in speed and areal coverage over traditional probing. However, to obtain quantitative mass-balance measurements from GPR images one needs to convert the time scale to a depth scale, not a straightforward problem. We compare a GPR section with dielectric profiles and visual stratigraphy of three snow cores, manual probings, and previous mass-balance measurements. We relate changes in snow-core dielectric properties to changes in density and to the travel times of reflecting horizons in the GPR section, and correlate some of these reflecting horizons with previous summer surfaces. We conclude that GPR can be used as a complementary tool in mass-balance measurements, giving a wide areal survey of winter accumulation and net balance for preceding years. However, proper calibration is essential for identifying specific surfaces in the radar data.

scholarly journals Minor Imbalance of the Lowermost Italian Glacier from 2006 to 2019

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2503
Author(s):  
Jessica De Marco ◽  
Luca Carturan ◽  
Livia Piermattei ◽  
Sara Cucchiaro ◽  
Daniele Moro ◽  
...  
Keyword(s):  
Mass Balance ◽  
Laser Scanning ◽  
Climate Changes ◽  
Average Rate ◽  
European Alps ◽  
Surface Dynamics ◽  
Solid Precipitation ◽  
Airborne Laser ◽  
Geodetic Mass Balance ◽  
Annual Balance

The response of very small glaciers to climate changes is highly scattered and little known in comparison with larger ice bodies. In particular, small avalanche-fed and debris-covered glaciers lack mass balance series of sufficient length. In this paper we present 13 years of high-resolution observations over the Occidentale del Montasio Glacier, collected using Airborne Laser Scanning, Terrestrial Laser Scanning, and Structure from Motion Multi-View Stereo techniques for monitoring its geodetic mass balance and surface dynamics. The results have been analyzed jointly with meteorological variables, and compared to a sample of “reference” glaciers for the European Alps. From 2006 to 2019 the mass balance showed high interannual variability and an average rate much closer to zero than the average of the Alpine reference glaciers (−0.09 vs. −1.42 m water equivalent per year, respectively). This behavior can be explained by the high correlation between annual balance and solid precipitation, which displayed recent peaks. The air temperature is not significantly correlated with the mass balance, which is main controlled by avalanche activity, shadowing and debris cover. However, its rapid increase is progressively reducing the fraction of solid precipitation, and increasing the length of the ablation season.

scholarly journals Using ground-penetrating radar to image previous years’ summer surfaces for mass-balance measurements

1997 ◽  
Vol 24 ◽  
pp. 355-360 ◽  
Author(s):  
Jack Kohler ◽  
John Moore ◽  
Mike Kennett ◽  
Rune Engeset ◽  
Hallgeir Elvehøy
Keyword(s):  
Dielectric Properties ◽  
Mass Balance ◽  
Ground Penetrating Radar ◽  
Radar Data ◽  
Snow Accumulation ◽  
Ice Surface ◽  
Winter Snow ◽  
Depth Scale ◽  
Ground Penetrating ◽  
Previous Summer

In traditional mass-balance measurements one estimates winter snow accumulation by identifying the depth to the previous summer’s snow or ice surface using a snow probe. This is labor-intensive and unreliable for inhomogeneous summer surfaces. Another method is to image internal reflection horizons using a ground-penetrating radar (GPR), which has advantages in speed and areal coverage over traditional probing. However, to obtain quantitative mass-balance measurements from GPR images one needs to convert the time scale to a depth scale, not a straightforward problem. We compare a GPR section with dielectric profiles and visual stratigraphy of three snow cores, manual probings, and previous mass-balance measurements. We relate changes in snow-core dielectric properties to changes in density and to the travel times of reflecting horizons in the GPR section, and correlate some of these reflecting horizons with previous summer surfaces. We conclude that GPR can be used as a complementary tool in mass-balance measurements, giving a wide areal survey of winter accumulation and net balance for preceding years. However, proper calibration is essential for identifying specific surfaces in the radar data.

Reconstructed Runoff from the High Arctic Basin Bayelva based on Mass-Balance Measurements

1995 ◽  
Vol 26 (4-5) ◽  
pp. 285-296 ◽  
Author(s):  
Jon Ove Hagen ◽  
Bernard Lefauconnier
Keyword(s):  
Mass Balance ◽  
Water Discharge ◽  
Monitoring Program ◽  
Arctic Basin ◽  
High Arctic ◽  
Annual Runoff ◽  
Snow Accumulation ◽  
Research Station ◽  
Winter Snow ◽  
Stable Conditions

The river Bayelva drains a catchment area of 31.5 km2 in the Kongsfjord area close to the research station Ny-Ålesund (79° N 12°E) on the northwest coast of Spitsbergen. The basin is 54% glacierized, and the studied glacier Austre Brøggerbreen is 6.1 km2 and constitutes 20% of the basin. On this glacier a mass-balance monitoring program including accumulation and ablation measurements has been carried out continuously since 1967. The winter snow accumulation shows very stable conditions with a mean accumulation of 0.71 ± 0.16 m/year in water equivalent. The runoff from the glacier in an equilibrium year should thus be 4.33 × 106 m3. The mean ablation on this glacier has been greater than the winter accumulation, 1.14 ± 0.26 m/year of water equivalent, which results in an annual runoff of 6.95 × 106 m3. That is more than 60% higher runoff from the glacier than in a year with zero net balance. The result is a mean net balance of – 0.42 m/year, or an annual runoff from the glacier due to the retreat of the glacier of 2.6 × 106 m3. In Bayelva, a runoff station was operated from 1974-1978. In 1988 this basin was chosen as a hydrological research site, and the runoff measurements were restarted and a permanent station for water discharge and sediment transport measurements was constructed in the river. This basin is the only one in Svalbard with some years of hydrological data. The water balance discussion shows that there is good agreement between the measured runoff in the river Bayelva and the potential runoff calculated from the mass-balance measurements on Brøggerbreen. On the basis of this correlation the total annual runoff was reconstructed from the whole period of mass-balance data from 1967-1991. The runoff from the whole basin has been 30% higher than in years with an equilibrium mass-balance on the glacier.

scholarly journals Influence of precipitation seasonality on glacier mass balance and its sensitivity to climate change

2008 ◽  
Vol 48 ◽  
pp. 88-92 ◽  
Author(s):  
Koji Fujita
Keyword(s):  
Mass Balance ◽  
Surface Albedo ◽  
Summer Precipitation ◽  
Arid Environment ◽  
Climatic Conditions ◽  
Snow Accumulation ◽  
Annual Precipitation ◽  
Glacier Mass Balance ◽  
Accumulation Pattern ◽  
Precipitation Seasonality

AbstractNumerical calculations are described, aimed at evaluating the influence of precipitation seasonality (summer and winter) on glacier mass balance. First, equilibrium-line altitudes (ELAs) are modeled using idealized meteorological variables. Modeled climatic conditions (summer mean temperature and annual precipitation) at the ELA of glaciers located within a winter accumulation pattern confirm the observational results of earlier studies. However, the ELA of glaciers located within a summer accumulation climate pattern locates in a colder environment than that of glaciers located within a winter accumulation climate pattern. This difference is mainly due to the annual snow accumulation and the surface albedo. A warming test (+1K) reveals higher sensitivities for the glaciers located within a summer accumulation pattern than for the glaciers located within a winter accumulation pattern. In a humid environment, a significant decrease in snow accumulation on the glaciers located within a summer accumulation pattern directly causes higher sensitivities. In an arid environment, on the other hand, the decreased summer snow induces accelerated melting by lowering the surface albedo and thus increasing absorption of solar radiation on the glaciers located within a summer accumulation pattern. Both influences are due to significant differences in summer precipitation. This study shows the importance of precipitation seasonality on the climatic sensitivity of glacier mass balance, which in previous studies has been linked only with annual precipitation.

scholarly journals Local- and Regional-Scale Forcing of Glacier Mass Balance Changes in the Swiss Alps

2021 ◽  
Vol 13 (10) ◽  
pp. 1949
Author(s):  
Saeideh Gharehchahi ◽  
Thomas J. Ballinger ◽  
Jennifer L. R. Jensen ◽  
Anshuman Bhardwaj ◽  
Lydia Sam ◽  
...  
Keyword(s):  
Mass Balance ◽  
Large Scale ◽  
Regional Scale ◽  
Atlantic Multidecadal Oscillation ◽  
Swiss Alps ◽  
Glacier Mass Balance ◽  
Landsat Images ◽  
Air Temperatures ◽  
Lake Formation ◽  
The Impact

Glacier mass variations are climate indicators. Therefore, it is essential to examine both winter and summer mass balance variability over a long period of time to address climate-related ice mass fluctuations. In this study we analyze glacier mass balance components and hypsometric characteristics with respect to their interactions with local meteorological variables and remote large-scale atmospheric and oceanic patterns. The results show that all selected glaciers have lost their equilibrium condition in recent decades, with persistent negative annual mass balance trends and decreasing accumulation area ratios (AARs), accompanied by increasing air temperatures of ≥+0.45 °C decade−1. The controlling factor of annual mass balance is mainly attributed to summer mass losses, which are correlated with (warming) June to September air temperatures. In addition, the interannual variability of summer and winter mass balances is primarily associated to the Atlantic Multidecadal Oscillation (AMO), Greenland Blocking Index (GBI), and East Atlantic (EA) teleconnections. Although climate parameters are playing a significant role in determining the glacier mass balance in the region, the observed correlations and mass balance trends are in agreement with the hypsometric distribution and morphology of the glaciers. The analysis of decadal frontal retreat using Landsat images from 1984 to 2014 also supports the findings of this research, highlighting the impact of lake formation at terminus areas on rapid glacier retreat and mass loss in the Swiss Alps.

scholarly journals Evolution of Ossoue Glacier (French Pyrenees) since the end of the Little Ice Age

2015 ◽  
Vol 9 (2) ◽  
pp. 2431-2494 ◽  
Author(s):  
R. Marti ◽  
S. Gascoin ◽  
T. Houet ◽  
O. Ribière ◽  
D. Laffly ◽  
...  
Keyword(s):  
Mass Balance ◽  
Little Ice Age ◽  
Atlantic Multidecadal Oscillation ◽  
Ablation Rate ◽  
Ice Age ◽  
Glacier Length ◽  
Geodetic Mass Balance ◽  
High Elevations ◽  
Topographic Surveys

Abstract. Long-term climate records are rare at high elevations in Southern Europe. Here, we reconstructed the evolution of Ossoue Glacier (42°46' N, 0.45 km2), located in the Pyrenees (3404 m a.s.l.), since the Little Ice Age (LIA). Glacier length, area, thickness and mass changes indicators were generated from historical datasets, topographic surveys, glaciological measurements (2001–2013), a GPR survey (2006) and stereoscopic satellite images (2013). The glacier has receded considerably since the end of the LIA, losing 40 % of its length and 60% of its area. Three periods of marked ice depletion can be identified: 1850–1890, 1928–1950 and 1983–2013, as well as two periods of stabilization or slightly growth: 1905–1928 and 1950–1983; these agree with climatic datasets (air temperature, precipitation, North Atlantic Oscillation, Atlantic Multidecadal Oscillation). In the early 2000s, the area of the glacier dropped below 50% of its area at the end of the LIA. Geodetic mass balance measurements over 1983–2013 indicated −30.1 ± 1.7 m w.e. (−1 m w.e. yr−1) whereas glaciological mass balance measurements show −17.36 ± 2.9 m w.e. (−1.45 m w.e. yr−1) over 2001–2013, resulting in a doubling of the ablation rate in the last decade. In 2013 the maximum ice thickness was 59 ± 10.3 m. Assuming that the current ablation rate stays constant, Ossoue Glacier will disappear midway through the 21st century.

Investigating global changes in snow dynamics and the impact on water resources

2020 ◽  
Author(s):  
Adrià Fontrodona Bach ◽  
Joshua Larsen ◽  
Ross Woods ◽  
Bettina Schaefli ◽  
Ryan Teuling
Keyword(s):  
Water Resources ◽  
Hydrological Cycle ◽  
Snow Accumulation ◽  
Global Changes ◽  
Hydrological Models ◽  
Winter Snow ◽  
Long Term Trends ◽  
And Shifts ◽  
The Impact

&lt;p&gt;Snow is a key component of the hydrological cycle in many regions of the world, providing a natural storage of water by accumulating snow in winter and releasing it in spring. Many ecosystems, societies and economies rely on this mechanism as a water resource. There is strong evidence in the literature that global warming leads to decreasing snowfall and snow accumulation and shifts the onset of the melt season to earlier in the year. However, little is known about how rising temperatures affect snowmelt rates and timing, and how these can have an impact on water resources for instance by changing the time and magnitude of streamflow. Some studies predict slower snowmelt rates in a warmer world, due to the onset of melt being earlier when there is less energy available for melt, but there is not yet an observation-based study showing such trends. As a first step, here we present preliminary results of observed long term trends in snowmelt rates from different climates. We use a dataset that has already shown strong decreasing signals for winter snow accumulation. Here we also present potential avenues to investigate the sensitivity of snowpacks and snowmelt regimes in different climatic settings to further rising temperatures using modeled snow dynamics. A few possibilities on how to link the snowpack dynamics to impacts in water resources are also discussed, for instance by comparing modelled dynamics to hydrological models and observations.&lt;/p&gt;

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