scholarly journals Intensified paraglacial slope failures due to accelerating downwasting of a temperate glacier in Mt. Gongga, southeastern Tibetan Plateau

2022 ◽  
Vol 10 (1) ◽  
pp. 23-42
Author(s):  
Yan Zhong ◽  
Qiao Liu ◽  
Matthew Westoby ◽  
Yong Nie ◽  
Francesca Pellicciotti ◽  
...  
Keyword(s):  
Mass Loss ◽  
Slope Failure ◽  
Geological Structure ◽  
Climatic Conditions ◽  
Slope Instability ◽  
High Mountain ◽  
Seasonal Temperature ◽  
Lateral Moraine ◽  
Mountain Areas ◽  
Mountain Glacier

Abstract. Topographic development via paraglacial slope failure (PSF) represents a complex interplay between geological structure, climate, and glacial denudation. Southeastern Tibet has experienced amongst the highest rates of ice mass loss in High Mountain Asia in recent decades, but few studies have focused on the implications of this mass loss on the stability of paraglacial slopes. We used repeat satellite- and unpiloted aerial vehicle (UAV)-derived imagery between 1990 and 2020 as the basis for mapping PSFs from slopes adjacent to Hailuogou Glacier (HLG), a 5 km long monsoon temperate valley glacier in the Mt. Gongga region. We observed recent lowering of the glacier tongue surface at rates of up to 0.88 m a−1 in the period 2000 to 2016, whilst overall paraglacial bare ground area (PBGA) on glacier-adjacent slopes increased from 0.31 ± 0.27 km2 in 1990 to 1.38 ± 0.06 km2 in 2020. Decadal PBGA expansion rates were ∼ 0.01 km2 a−1, 0.02 km2 a−1, and 0.08 km2 in the periods 1990–2000, 2000–2011, and 2011–2020 respectively, indicating an increasing rate of expansion of PBGA. Three types of PSFs, including rockfalls, sediment-mantled slope slides, and headward gully erosion, were mapped, with a total area of 0.75 ± 0.03 km2 in 2020. South-facing valley slopes (true left of the glacier) exhibited more destabilization (56 % of the total PSF area) than north-facing (true right) valley slopes (44 % of the total PSF area). Deformation of sediment-mantled moraine slopes (mean 1.65–2.63 ± 0.04 cm d−1) and an increase in erosion activity in ice-marginal tributary valleys caused by a drop in local base level (gully headward erosion rates are 0.76–3.39 cm d−1) have occurred in tandem with recent glacier downwasting. We also observe deformation of glacier ice, possibly driven by destabilization of lateral moraine, as has been reported in other deglaciating mountain glacier catchments. The formation, evolution, and future trajectory of PSFs at HLG (as well as other monsoon-dominated deglaciating mountain areas) are related to glacial history, including recent rapid downwasting leading to the exposure of steep, unstable bedrock and moraine slopes, and climatic conditions that promote slope instability, such as very high seasonal precipitation and seasonal temperature fluctuations that are conducive to freeze–thaw and ice segregation processes.

scholarly journals Research advances on climate-induced slope instability in glacier and permafrost high-mountain environments

2010 ◽  
Vol 65 (2) ◽  
pp. 146-156 ◽  
Author(s):  
C. Huggel ◽  
L. Fischer ◽  
D. Schneider ◽  
W. Haeberli
Keyword(s):  
Slope Failure ◽  
Hazard Analysis ◽  
Slope Instability ◽  
High Mountain ◽  
Temperature Sensitive ◽  
Mountain Areas ◽  
Mountain Environments ◽  
Slope Instabilities ◽  
Monte Rosa ◽  
Insight Into

Abstract. High-mountain areas with glacier and permafrost occurrence are temperature sensitive environments. Climatic changes are, thus, likely to have an effect on slope stability. Several recent events have shown that rock and ice avalanches and related hazards can have severe consequences. For hazard analysis, the processes of slope failure and flow dynamics should therefore be better understood. In this article, recent advances in this field are presented, including high-resolution topographic monitoring of a large Alpine high-mountain flank (Monte Rosa) over the past 50 years and laboratory experiments with rotating drums and numerical modelling. This recent research has revealed important insight into the causes and dynamics of slope instabilities and contributes towards a better understanding of the influence of ice on avalanche dynamics and runout. It is emphasized that high-mountain slope failures need to be viewed from an interdisciplinary perspective, taking a number of process interactions into account.

scholarly journals Formation Patterns of Mediterranean High-Mountain Water-Bodies in Sierra-Nevada, SE Spain

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 438
Author(s):  
Jose Luis Diaz-Hernandez ◽  
Antonio Jose Herrera-Martinez
Keyword(s):  
Sierra Nevada ◽  
Unknown Origin ◽  
Slope Instability ◽  
Water Bodies ◽  
High Mountain ◽  
Mountain Areas ◽  
Glacial Processes ◽  
The Mediterranean ◽  
Water Volumes

At present, there is a lack of detailed understanding on how the factors converging on water variables from mountain areas modify the quantity and quality of their watercourses, which are features determining these areas’ hydrological contribution to downstream regions. In order to remedy this situation to some extent, we studied the water-bodies of the western sector of the Sierra Nevada massif (Spain). Since thaw is a necessary but not sufficient contributor to the formation of these fragile water-bodies, we carried out field visits to identify their number, size and spatial distribution as well as their different modelling processes. The best-defined water-bodies were the result of glacial processes, such as overdeepening and moraine dams. These water-bodies are the highest in the massif (2918 m mean altitude), the largest and the deepest, making up 72% of the total. Another group is formed by hillside instability phenomena, which are very dynamic and are related to a variety of processes. The resulting water-bodies are irregular and located at lower altitudes (2842 m mean altitude), representing 25% of the total. The third group is the smallest (3%), with one subgroup formed by anthropic causes and another formed from unknown origin. It has recently been found that the Mediterranean and Atlantic watersheds of this massif are somewhat paradoxical in behaviour, since, despite its higher xericity, the Mediterranean watershed generally has higher water contents than the Atlantic. The overall cause of these discrepancies between watersheds is not connected to their formation processes. However, we found that the classification of water volumes by the manners of formation of their water-bodies is not coherent with the associated green fringes because of the anomalous behaviour of the water-bodies formed by moraine dams. This discrepancy is largely due to the passive role of the water retained in this type of water-body as it depends on the characteristics of its hollows. The water-bodies of Sierra Nevada close to the peak line (2918 m mean altitude) are therefore highly dependent on the glacial processes that created the hollows in which they are located. Slope instability created water-bodies mainly located at lower altitudes (2842 m mean altitude), representing tectonic weak zones or accumulation of debris, which are influenced by intense slope dynamics. These water-bodies are therefore more fragile, and their existence is probably more short-lived than that of bodies created under glacial conditions.

scholarly journals Chromosomal Q-Heterochromatin and Atherosclerosis

2017 ◽  
Vol 7 (1) ◽  
pp. 143
Author(s):  
A. I. Ibraimov
Keyword(s):  
Homo Sapiens ◽  
Single Species ◽  
Causative Factor ◽  
Mean Value ◽  
Biological Species ◽  
Climatic Conditions ◽  
Cold Climate ◽  
High Mountain ◽  
Mountain Areas ◽  
Blood Temperature

We suppose that at study of the pathogenesis of atherosclerosis, it is possible that some evolutionary aspects of the problem are missed. This aspect is related to the peculiarity of human adaptation to climatic geographic conditions of Eurasia, which differ significantly from the climate of East Africa, where Homo sapiens was formed as a tropical biological species and so it has remained to this day. A hypothesis has been put forward that the pathogenesis of atherosclerosis is associated with some previously unknown features of the genome and the physical properties of the human body that arose in the process of its adaptation to a mild and cold climate. These adaptive genetic changes that have contributed to the development (settling) by Homo sapiens of non-tropical, including cold and high mountain areas of the Earth, resulted to the fact that a man became the single species vulnerable (predisposed) to atherosclerosis.Atherosclerosis is apparently a purely human disease that appeared after adaptation of man to climatic conditions of temperate and northern latitudes of the northern hemisphere. The type of vessels (arteries or veins) and the site of their lumen have no role in the development of atherosclerotic changes. The primary and main causative factor in the development of atherosclerosis is blood temperature. The degree of blood cooling in the lungs depends on geographical latitudes and altitude above sea-level of the site of permanent residence of man. The preclinical stage of atherosclerosis may develop into a pathological form predominantly in individuals in the genome of which the amount of chromosomal Q-heterochromatin material is higher than its mean value per individual in the population.

scholarly journals Impacts of Glacier-Related Landslides on the Settlement at Hopar, Karakoram Himalaya

1989 ◽  
Vol 13 ◽  
pp. 185-188 ◽  
Author(s):  
K.I. MacDonald
Keyword(s):  
Social Change ◽  
Slope Instability ◽  
High Mountain ◽  
Daily Routine ◽  
Northern Pakistan ◽  
Mountain Areas ◽  
Ice Surface ◽  
Wage Labour ◽  
Irrigation Channels

Slope instability and occasional devastating landslides are well-known hazards in high mountain areas. This paper describes and discusses an example of extensive and recurring damage associated with agricultural settlements around the lower reaches of the rapidly flowing Bualtar and Barpu Glaciers in northern Pakistan. These landslides occur over a zone about 20 km long in response to erosive processes at the ice-slope interface, and slowly descend 150–300 m from the edges of cultivation to the glacier margins. Damage is evident in the loss and/or abandonment of approximately 10 km2 of land, and in the destruction of dwellings and irrigation channels. The daily routine of local villagers is affected because alterations of both the slope and the ice surface destroy frequently used transport routes. Although the landslides have a history decades long, the landslide problem has more recently assumed heightened significance in relation to rapidly occurring economic and social change such as the introduction of wage labour and seasonal outmigration.

scholarly journals Landscape diversity and biodiversity of Fann Mountains (Tajikistan)

2013 ◽  
Vol 32 (4) ◽  
Author(s):  
Oimahmad Rahmonov ◽  
Leszek Majgier ◽  
Wiaczesław Andrejczuk ◽  
Jarosław Banaszek ◽  
Dominik Karkosz ◽  
...  
Keyword(s):  
Endemic Species ◽  
Deciduous Forest ◽  
Flood Plain ◽  
Geological Structure ◽  
Climatic Conditions ◽  
Landscape Diversity ◽  
High Mountain ◽  
Climate Conditions ◽  
Shrub Steppe ◽  
High Level

AbstractRahmonov O., Majgier L., Andrejczuk W., Banaszek J., Karkosz D., Parusel T., Szymczyk A.: Landscape diversity and biodiversity of Fann Mountains (Tajikistan). Ekologia (Bratislava), Vol. 32, No. 4, p. 388-395, 2013.The aim of study is a presentation of main vegetation landscape diversity and biodiversity in case of endemic species in the Fann Mountains area, in horizontal and vertical approach. In terms of biodiversity, the high-mountain ecosystems of Central Asia include the most valuable areas in the world called as hotspot, and also are exposed to intense human pressure causing the destruction of habitats. Vegetation landscapes of Fann Mountains are very diverse because of high-mountain character of this area, local climatic conditions, topography and habitats. That differentiation leads up to biodiversity and formation of unique plant landscapes and endemic species. The vegetation landscapes in altitude order are represented by forbs meadow steppe, thymes, swamp, broad-leaf forest, juniper forests, flood-plain small-leaved forest, tugai, light deciduous forest, pistachio, forbs wormwood, almond, rare vegetation with cushion-shaped species, wormwood eurotia, steppe, thorny grasses with shrub-steppe, rocks and taluses with rare vegetation alpine zones. High level of endemism in Fann Mountains is connected to natural conditions such as geological structure, relief, high-mountain ranges and climate conditions. This fact has an influence on forming mosaic biotops, often isolated by orographic barriers.

scholarly journals On the influence of topographic, geological and cryospheric factors on rock avalanches and rockfalls in high-mountain areas

2012 ◽  
Vol 12 (1) ◽  
pp. 241-254 ◽  
Author(s):  
L. Fischer ◽  
R. S. Purves ◽  
C. Huggel ◽  
J. Noetzli ◽  
W. Haeberli
Keyword(s):  
Slope Failure ◽  
Temporal Distribution ◽  
High Mountain ◽  
European Alps ◽  
Permafrost Degradation ◽  
Slope Failures ◽  
Mountain Areas ◽  
Investigation Area ◽  
Rock Avalanches ◽  
Slope Instabilities

Abstract. The ongoing debate about the effects of changes in the high-mountain cryosphere on rockfalls and rock avalanches suggests a need for more knowledge about characteristics and distribution of recent rock-slope instabilities. This paper investigates 56 sites with slope failures between 1900 and 2007 in the central European Alps with respect to their geological and topographical settings and zones of possible permafrost degradation and glacial recession. Analyses of the temporal distribution show an increase in frequency within the last decades. A large proportion of the slope failures (60%) originated from a relatively small area above 3000 m a.s.l. (i.e. 10% of the entire investigation area). This increased proportion of detachment zones above 3000 m a.s.l. is postulated to be a result of a combination of factors, namely a larger proportion of high slope angles, high periglacial weathering due to recent glacier retreat (almost half of the slope failures having occurred in areas with recent deglaciation), and widespread permafrost occurrence. The lithological setting appears to influence volume rather than frequency of a slope failure. However, our analyses show that not only the changes in cryosphere, but also other factors which remain constant over long periods play an important role in slope failures.

scholarly journals Transient thermal effects in Alpine permafrost

2009 ◽  
Vol 3 (1) ◽  
pp. 85-99 ◽  
Author(s):  
J. Noetzli ◽  
S. Gruber
Keyword(s):  
Climatic Conditions ◽  
Balance Model ◽  
High Mountain ◽  
Transient Effects ◽  
Mountain Areas ◽  
Past Climate ◽  
Climate Conditions ◽  
The Past ◽  
Numerical Experimentation ◽  
Time Periods

Abstract. In high mountain areas, permafrost is important because it influences the occurrence of natural hazards, because it has to be considered in construction practices, and because it is sensitive to climate change. The assessment of its distribution and evolution is challenging because of highly variable conditions at and below the surface, steep topography and varying climatic conditions. This paper presents a systematic investigation of effects of topography and climate variability that are important for subsurface temperatures in Alpine bedrock permafrost. We studied the effects of both, past and projected future ground surface temperature variations on the basis of numerical experimentation with simplified mountain topography in order to demonstrate the principal effects. The modeling approach applied combines a distributed surface energy balance model and a three-dimensional subsurface heat conduction scheme. Results show that the past climate variations that essentially influence present-day permafrost temperatures at depth of the idealized mountains are the last glacial period and the major fluctuations in the past millennium. Transient effects from projected future warming, however, are likely larger than those from past climate conditions because larger temperature changes at the surface occur in shorter time periods. We further demonstrate the accelerating influence of multi-lateral warming in steep and complex topography for a temperature signal entering the subsurface as compared to the situation in flat areas. The effects of varying and uncertain material properties (i.e., thermal properties, porosity, and freezing characteristics) on the subsurface temperature field were examined in sensitivity studies. A considerable influence of latent heat due to water in low-porosity bedrock was only shown for simulations over time periods of decades to centuries. At the end, the model was applied to the topographic setting of the Matterhorn (Switzerland). Results from idealized geometries are compared to this first example of real topography, and possibilities as well as limitations of the model application are discussed.

Global differences in the energy balance and melt rates of debris-covered glacier surfaces

2021 ◽  
Author(s):  
Evan Miles ◽  
Jakob Steiner ◽  
Pascal Buri ◽  
Walter Immerzeel ◽  
Francesca Pellicciotti
Keyword(s):  
Energy Balance ◽  
Wind Speed ◽  
Surface Energy ◽  
Mass Loss ◽  
Energy Absorption ◽  
Random Sets ◽  
Physical Parameters ◽  
High Mountain ◽  
Glacier Surface ◽  
Mountain Glacier

<p>Supraglacial debris covers 4% of mountain glacier area globally and generally reduces glacier surface melt. Studies have identified enhanced energy absorption at ice cliffs and supraglacial ponds scattered across the debris surface. Although these features generally cover a small portion of glacier surface area (5-10%) they contribute disproportionately to mass loss at the local glacier scales (20-40%). While past studies have identified their melt-enhancing role in High Mountain Asia, Alaska, and the Alps, it is not clear to what degree they enhance mass loss in other areas of the globe.</p><p>We model the surface energy balance for debris-covered ice, ice cliffs, and supraglacial ponds using meteorological records (4 radiative fluxes, wind speed, air temperature, humidity) from a set of on-glacier automated weather stations representing the global prevalence of debris covered glaciers. We generate 5000 random sets of values for physical parameters using probability distributions derived from literature. We also model the hypothetical energy balance of a debris-free glacier surface at each site, which we use to investigate the melt rates of distinct surface types relative to that of a clean ice glacier. This approach allows us to isolate the melt responses of debris, cliffs and ponds to the site specific meteorological forcing.</p><p>For each site we determine an Østrem curve for sub-debris melt as a function of debris thickness and a probabilistic understanding of surface energy absorption for ice cliffs, supraglacial ponds, and debris-covered ice. While debris leads to strong reductions in melt at all sites, we find an order-of-magnitude spread in sub-debris melt rates due solely to climatic differences between sites. The melt enhancement of ice cliffs relative to debris-covered ice is starkly apparent at all sites, and ice cliffs melt rates are generally 1.5-2.5 times the ablation rate for a clean ice surface. The supraglacial pond energy balance varies regionally, and is sensitive to wind speed and relative humidity, leading to energy absorption 0.4-1.2 times that of clean ice, but 5-10 times higher than debris-covered ice. Our results support the few past assessments of melt rates for cliffs and ponds, and indicate sub-regional coherence in the energy balance response of these features to climate.</p>

scholarly journals Impacts of Glacier-Related Landslides on the Settlement at Hopar, Karakoram Himalaya

1989 ◽  
Vol 13 ◽  
pp. 185-188
Author(s):  
K.I. MacDonald
Keyword(s):  
Social Change ◽  
Slope Instability ◽  
High Mountain ◽  
Daily Routine ◽  
Northern Pakistan ◽  
Mountain Areas ◽  
Ice Surface ◽  
Wage Labour ◽  
Irrigation Channels

Slope instability and occasional devastating landslides are well-known hazards in high mountain areas. This paper describes and discusses an example of extensive and recurring damage associated with agricultural settlements around the lower reaches of the rapidly flowing Bualtar and Barpu Glaciers in northern Pakistan. These landslides occur over a zone about 20 km long in response to erosive processes at the ice-slope interface, and slowly descend 150–300 m from the edges of cultivation to the glacier margins. Damage is evident in the loss and/or abandonment of approximately 10 km2 of land, and in the destruction of dwellings and irrigation channels. The daily routine of local villagers is affected because alterations of both the slope and the ice surface destroy frequently used transport routes. Although the landslides have a history decades long, the landslide problem has more recently assumed heightened significance in relation to rapidly occurring economic and social change such as the introduction of wage labour and seasonal outmigration.

scholarly journals Transient thermal effects in Alpine permafrost

2008 ◽  
Vol 2 (2) ◽  
pp. 185-224 ◽  
Author(s):  
J. Noetzli ◽  
S. Gruber
Keyword(s):  
Thermal State ◽  
Ground Surface ◽  
Climatic Conditions ◽  
Balance Model ◽  
High Mountain ◽  
Complex Topography ◽  
Transient Effects ◽  
Mountain Areas ◽  
The Past ◽  
Numerical Experimentation

Abstract. In high mountain areas, permafrost is important because it influences natural hazards and construction practices, and because it is an indicator of climate change. The modeling of its distribution and evolution over time is complicated by steep and complex topography, highly variable conditions at and below the surface, and varying climatic conditions. This paper presents a systematic investigation of effects of climate variability and topography that are important for subsurface temperatures in Alpine permafrost areas. The effects of both past and projected future ground surface temperature variations on the thermal state of Alpine permafrost are studied based on numerical experimentation with simplified mountain topography. For this purpose, we use a surface energy balance model together with a subsurface heat conduction scheme. The past climate variations that essentially influence the present-day permafrost temperatures at depth are the last glacial period and the major fluctuations in the past millennium. The influence of projected future warming was assessed to cause even larger transient effects in the subsurface thermal field because warming occurs on shorter time scales. Results further demonstrate the accelerating influence of multi-lateral warming in Alpine topography for a temperature signal entering the subsurface. The effects of thermal properties, porosity, and freezing characteristics were examined in sensitivity studies. A considerable influence of latent heat due to water in low-porosity bedrock was only shown for simulations over shorter time periods (i.e., decades to centuries). Finally, as an example of a real and complex topography, the modeled transient three-dimensional temperature distribution in the Matterhorn (Switzerland) is given for today and in 200 years.

Sign in / Sign up

Export Citation Format

Share Document