scholarly journals Brief communication: Supraglacial debris-cover changes in the Caucasus Mountains

2019 ◽  
Author(s):  
Levan G. Tielidze ◽  
Tobias Bolch ◽  
Roger D. Wheate ◽  
Stanislav S. Kutuzov ◽  
Ivan I. Lavrentiev ◽  
...  
Keyword(s):  
Morphological Type ◽  
Ice Age ◽  
Slope Aspect ◽  
Glacier Mass Balance ◽  
The Caucasus ◽  
Greater Caucasus ◽  
Time Period ◽  
Covered Area ◽  
Debris Cover ◽  
Caucasus Mountains

Abstract. Debris cover on glaciers can significantly alter melt, and hence, glacier mass balance and runoff. Debris coverage typically increases with shrinking glaciers. Here, we present data on debris cover and its changes for 559 glaciers located in different regions of the Greater Caucasus mountains based on 1986, 2000 and 2014 Landsat and SPOT images. Over this time period, the total glacier area decreased from 691.5 km2 to 590.0 km2 (0.52 % yr−1). Thereby, the debris covered area increased from ~ 11 to ~ 24 % on the northern, and from ~ 4 to 10 % on the southern macro-slope between 1986 and 2014. Overall, we found 18 % debris cover for the year 2014. With the glacier shrinkage, debris-covered area and the number of debris-covered glaciers increased as a function of elevation, slope, aspect, glacier morphological type, Little Ice Age moraines, and lithology.

scholarly journals Supraglacial debris cover assessment in the Caucasus Mountains, 1986-2000-2014

2017 ◽  
Author(s):  
Levan G. Tielidze ◽  
Roger D. Wheate ◽  
Stanislav S. Kutuzov ◽  
Kate Doyle ◽  
Ivan I. Lavrentiev
Keyword(s):  
Morphological Type ◽  
Ice Age ◽  
Landsat 8 ◽  
Glacier Area ◽  
Greater Caucasus ◽  
Rock Structure ◽  
Debris Cover ◽  
Landsat 7 ◽  
Caucasus Mountains ◽  
Elevation Model

Abstract. Surpaglacial debris cover plays an increasingly important role impacting on glacier ablation, while there have been limited recent studies for the assessment of debris covered glaciers in the Greater Caucasus mountains. We selected 559 glaciers according to the sections and macroslopes in the Greater Caucasus main watershed range and the Elbrus massif to assess supraglacial debris cover (SDC) for the years 1986, 2000 and 2014. Landsat (Landsat 5 TM, Landsat 7 ETM+, Landsat 8 OLI) and SPOT satellite imagery were analysed to generate glacier outlines using manual and semi-automated methods, along with slope information from a Digital Elevation Model. The study shows there is greater SDC area on the northern than the southern macroslope, and more in the eastern section than the western and central. In 1986-2000-2014, the SDC area increased from 6.4 %-8.2 %-19.4 % on the northern macroslope (apart from the eastern Greater Caucasus section), while on the southern macroslope, SDC increased from 4.0 %-4.9 %-9.2 %. Overall, debris covered glacier numbers increased from 122-143-172 (1986-2000-2014) for 559 selected glaciers. Despite the total glacier area decrease, the SDC glacier area and numbers increased as a function of slope inclination, aspect, glacier morphological type, Little Ice Age (LIA) moraines, rock structure and elevation. The datasets are available for public download at https://doi.pangaea.de/10.1594/PANGAEA.880147.

scholarly journals Supra-glacial debris cover changes in the Greater Caucasus from 1986 to 2014

2020 ◽  
Vol 14 (2) ◽  
pp. 585-598 ◽  
Author(s):  
Levan G. Tielidze ◽  
Tobias Bolch ◽  
Roger D. Wheate ◽  
Stanislav S. Kutuzov ◽  
Ivan I. Lavrentiev ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Google Earth ◽  
Gps Data ◽  
Glacier Area ◽  
Greater Caucasus ◽  
Abstract Knowledge ◽  
Covered Area ◽  
Debris Cover ◽  
Automated Methods

Abstract. Knowledge of supra-glacial debris cover and its changes remain incomplete in the Greater Caucasus, in spite of recent glacier studies. Here we present data of supra-glacial debris cover for 659 glaciers across the Greater Caucasus based on Landsat and SPOT images from the years 1986, 2000 and 2014. We combined semi-automated methods for mapping the clean ice with manual digitization of debris-covered glacier parts and calculated supra-glacial debris-covered area as the residual between these two maps. The accuracy of the results was assessed by using high-resolution Google Earth imagery and GPS data for selected glaciers. From 1986 to 2014, the total glacier area decreased from 691.5±29.0 to 590.0±25.8 km2 (15.8±4.1 %, or ∼0.52 % yr−1), while the clean-ice area reduced from 643.2±25.9 to 511.0±20.9 km2 (20.1±4.0 %, or ∼0.73 % yr−1). In contrast supra-glacial debris cover increased from 7.0±6.4 %, or 48.3±3.1 km2, in 1986 to 13.4±6.2 % (∼0.22 % yr−1), or 79.0±4.9 km2, in 2014. Debris-free glaciers exhibited higher area and length reductions than debris-covered glaciers. The distribution of the supra-glacial debris cover differs between the northern and southern and between the western, central and eastern Greater Caucasus. The observed increase in supra-glacial debris cover is significantly stronger on the northern slopes. Overall, we have observed up-glacier average migration of supra-glacial debris cover from about 3015 to 3130 m a.s.l. (metres above sea level) during the investigated period.

scholarly journals Late-20th-century changes in glacier extent in the Caucasus Mountains, Russia/Georgia

2006 ◽  
Vol 52 (176) ◽  
pp. 99-109 ◽  
Author(s):  
Chris R. Stokes ◽  
Stephen D. Gurney ◽  
Maria Shahgedanova ◽  
Victor Popovnin
Keyword(s):  
Field Measurements ◽  
Thematic Mapper ◽  
Ice Age ◽  
Late 20Th Century ◽  
The Caucasus ◽  
Central Caucasus ◽  
Caucasus Mountains ◽  
1960S And 1970S ◽  
Colour Composite ◽  
The 1960S

AbstractGlaciers occupy an area of ~1600km2 in the Caucasus Mountains. There is widespread evidence of retreat since the Little Ice Age, but an up-to-date regional assessment of glacier change is lacking. In this paper, satellite imagery (Landsat Thematic Mapper and Enhanced Thematic Mapper Plus) is used to obtain the terminus position of 113 glaciers in the central Caucasus in 1985 and 2000, using a manual delineation process based on a false-colour composite (bands 5, 4, 3). Measurements reveal that 94% of the glaciers have retreated, 4% exhibited no overall change and 2% advanced. The mean retreat rate equates to ~8ma–1, and maximum retreat rates approach ~38 m a–1. The largest (>10 km2) glaciers retreated twice as much (~12ma–1) as the smallest (<1 km2) glaciers (~6ma–1), and glaciers at lower elevations generally retreated greater distances. Supraglacial debris cover has increased in association with glacier retreat, and the surface area of bare ice has reduced by ~10% between 1985 and 2000. Results are compared to declassified Corona imagery from the 1960s and 1970s and detailed field measurements and mass-balance data for Djankuat glacier, central Caucasus. It is concluded that the decrease in glacier area appears to be primarily driven by increasing temperatures since the 1970s and especially since the mid-1990s. Continued retreat could lead to considerable changes in glacier runoff, with implications for regional water resources.

scholarly journals YORKSHIRE FOG (HOLCUS LANATUS). ITS POTENTIAL AS A PASTURE SPECIES

1973 ◽  
pp. 249-257
Author(s):  
W.A. Jacques
Keyword(s):  
South Africa ◽  
West Africa ◽  
Iberian Peninsula ◽  
Ice Age ◽  
Holcus Lanatus ◽  
The Caucasus ◽  
North West ◽  
Caucasus Mountains

YORKSHIRE FOG probably has its origin in the Iberian Peninsula (Vinal and Hein, 1937) but, as a result of continued colonization since the end of the ice age, is now found throughout Europe from the limiits of northern Scandinavia and Iceland to the Caucasus Mountains and North West Africa (Beddows, 1961; Hulten, 1950; Bother and Larsen, 1958). Under the influence of human pastoral activities, the species has spread to all of the more recently developed farming areas in the temperate regions of the Americas, South Africa and Australasia.

scholarly journals Ice ablation and meteorological conditions on the debris-covered area of Baltoro glacier, Karakoram, Pakistan

2006 ◽  
Vol 43 ◽  
pp. 292-300 ◽  
Author(s):  
Claudia Mihalcea ◽  
Christoph Mayer ◽  
Guglielmina Diolaiuti ◽  
Astrid Lambrecht ◽  
Claudio Smiraglia ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Field Experiments ◽  
Meteorological Data ◽  
Meteorological Conditions ◽  
Lapse Rate ◽  
Slope Aspect ◽  
Test Field ◽  
Climate Data ◽  
Covered Area ◽  
Debris Cover

AbstractDuring the recent Italian expedition ‘K2 2004 – 50 years later’ (June–July 2004) on Baltoro glacier, Karakoram, Pakistan, glaciological field experiments were carried out on the debris-covered area of this high-elevation glacier. The aim was to investigate the ice ablation and its relations with debris thermal properties and meteorological conditions. Ablation measurements along the glacier up to about 5000 m and within a dedicated test field were combined with meteorological data from two automatic weather stations located at Urdukas (4022 ma.s.l.) and at K2 Base Camp (5033 m a.s.l.). In addition, temperature measurements of the debris cover at different depth levels along the glacier allowed the calculation of debris surface temperature and of the debris thermal resistance (R). Using the air temperature, the local mean lapse rate (0.0075˚C m−1) and the measured ablation, the degree-day factors (K) at different locations on the glacier were calculated. The ice ablation rates were related to debris thickness and elevation. They are typically on the order of 4 cm d−1 during the observation period. However, it was found that the surface topography (slope, aspect) has an influence on the total ablation similar to that of the debris thickness. Thermal resistance of the debris cover and its distribution over the glacier were estimated. Finally, a best-guess estimate of the total meltwater production was calculated from available climate data.

scholarly journals A comparison of glacier melt on debris-covered glaciers in the northern and southern Caucasus

2011 ◽  
Vol 5 (3) ◽  
pp. 525-538 ◽  
Author(s):  
A. Lambrecht ◽  
C. Mayer ◽  
W. Hagg ◽  
V. Popovnin ◽  
A. Rezepkin ◽  
...  
Keyword(s):  
Field Experiments ◽  
Field Measurements ◽  
Special Focus ◽  
European Alps ◽  
The Caucasus ◽  
The North ◽  
Glacier Melt ◽  
Significant Difference ◽  
Debris Cover ◽  
Caucasus Mountains

Abstract. The glacier coverage in the Caucasus Mountains underwent considerable changes during the last decades. In some regions, the observed reduction in glacier area is comparable to those in the European Alps and the extent of supra-glacial debris increased on many glaciers. Only a few glaciers in the Caucasus are monitored on a regular basis, while for most areas no continuous field measurements are available. In this study, regional differences of the conditions for glacier melt with a special focus on debris covered glacier tongues in the well-studied Adyl-su basin on the northern slope of the Caucasus Mountains (Russia) is compared with the Zopkhito basin which has similar characteristics but is located on the southern slope in Georgia. The paper focuses on the effect of supra-glacial debris cover on glacier summer melt. There are systematic differences in the distribution and increase of the debris cover on the glaciers of the two basins. In the Adyl-su basin an extensive debris cover on the glacier tongues is common, however, only those glacier tongues that are positioned at the lowest elevations in the Zopkhito basin show a considerable extent of supra-glacial debris. The observed increase in debris cover is considerably stronger in the north. Field experiments show that thermal resistance of the debris cover in both basins is somewhat higher than in other glaciated regions of the world, but there is also a significant difference between the two regions. A simple ablation model accounting for the effect of debris cover on ice melt shows that melt rates are considerably higher in the northern basin despite a wider debris distribution. This difference between the two regions can be attributed to different meteorological conditions which are characterised by more frequent cloud cover and precipitation in the south. Furthermore ablation is strongly influenced by the occurrence of supra-glacial debris cover in both basins, reducing the total amount of melt on the studied glaciers by about 25 %. This effect mitigates glacier retreat in the lower sectors of the ablation zones considerably. The sensitivity to moderate changes in the debris cover, however, is rather small which implies only gradual changes of the melt regime due to debris cover dynamics during the near future.

The main characteristics of the wrinkled relief on the southern slope of the Greater Caucasus

2021 ◽  
Vol 09 (04) ◽  
pp. 24-26
Author(s):  
Qüdrət Tərlan oğlu Məmmədli ◽  
Keyword(s):  
Key Words ◽  
Southern Slope ◽  
The South ◽  
The Caucasus ◽  
Greater Caucasus ◽  
Mountainous Regions ◽  
South Eastern ◽  
Mountain System ◽  
Caucasus Mountains

Like other mountainous regions of the Caucasus, the South-Eastern Caucasus is an epigeosynclinal mountain system formed by the first and middle alpine folds. Between the Alpine fold stage and the orogenic stage, the South-East Caucasus Mountains were denuded and turned into hilly, low mountain plains in the Oligocene and Miocene. Wrinkled structures were destroyed by denudation and a mostly neutral relief type was formed. Key words: Greater Caucasus, southern slope of the Greater Caucasus, morphostructure, wrinkled relief, geological development

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