scholarly journals Ice Avalanche Activity and Mass Balance of a High-Altitude Hanging Glacier in the Swiss Alps

1985 ◽  
Vol 6 ◽  
pp. 248-249 ◽  
Author(s):  
Jürg Alean
Keyword(s):  
Seasonal Variation ◽  
High Altitude ◽  
Mass Balance ◽  
Swiss Alps ◽  
Average Mass ◽  
The Past ◽  
Predominant Form ◽  
Glacier Ice ◽  
Ice Avalanche

An estimation of average mass balance of a high hanging glacier in the Swiss Alps was made by measuring volumes of ice avalanches originating from this glacier. Ice avalanches are this glacier’s predominant form of ablation. Since the volume of the glacier has not noticeably changed over the past few years, the annual ice loss due to ice avalanches can be taken as an indication of average total net acumulation above the ice cliff where the avalanches originate. The mass balance value, as determined by recording ice avalanches, compares well with values obtained by independent methods (measurements of firn stratigraphy in the cliff, direct accumulation measurements in the vicinity). No seasonal variation in the frequency of ice avalanche occurence was detected.

scholarly journals Ice Avalanche Activity and Mass Balance of a High-Altitude Hanging Glacier in the Swiss Alps

1985 ◽  
Vol 6 ◽  
pp. 248-249 ◽  
Author(s):  
Jürg Alean
Keyword(s):  
Seasonal Variation ◽  
High Altitude ◽  
Mass Balance ◽  
Swiss Alps ◽  
Average Mass ◽  
The Past ◽  
Predominant Form ◽  
Glacier Ice ◽  
Ice Avalanche

An estimation of average mass balance of a high hanging glacier in the Swiss Alps was made by measuring volumes of ice avalanches originating from this glacier. Ice avalanches are this glacier’s predominant form of ablation. Since the volume of the glacier has not noticeably changed over the past few years, the annual ice loss due to ice avalanches can be taken as an indication of average total net acumulation above the ice cliff where the avalanches originate. The mass balance value, as determined by recording ice avalanches, compares well with values obtained by independent methods (measurements of firn stratigraphy in the cliff, direct accumulation measurements in the vicinity). No seasonal variation in the frequency of ice avalanche occurence was detected.

scholarly journals Changes in Eurasian glaciation during the past century: glacier mass balance and ice-core evidence

1997 ◽  
Vol 24 ◽  
pp. 283-287 ◽  
Author(s):  
Vladimir N. Mikhalenko
Keyword(s):  
Mass Balance ◽  
Ice Core ◽  
Climatic Conditions ◽  
Tien Shan ◽  
The Arctic ◽  
Past Century ◽  
Glacier Mass Balance ◽  
The Past ◽  
Ice Cap ◽  
Glacier Ice

Glaciers of both the Arctic and mid-latitude mountain systems within Eurasia have retreated intensively during the past century. Measured and reconstructed glacier mass balances show that glacier retreat began around the 1880s. The mean annual mass-balance value for 1880–1990 was −480 mm a−1 for glaciers with maritime climatic conditions, and −140 mm a−1 for continental glaciers. It can be concluded that warming in the Caucasus occurred during at least the last 60 years, according to the distribution of crystal sizes in an ice core from the Dzhantugan firn plateau. Temperatures measured in 1962 at 20 m on the Gregoriev ice cap, Tien Shan, were −4.2°C while in 1990 they were −2°C, a warming of 2.2°C over 28 years. Changes in the isotopic composition of glacier ice during the 20th century indicate recent and continuing warming in different regions of Eurasia. The δ18O records reveal an enrichment at the Gregoriev ice cap during the last 50 years, while surface temperatures at the Tien Shan meteorological station have increased 0.5°C since 1930.

scholarly journals Decadal evolution of a very small heavily debris-covered glacier in an Alpine permafrost environment

2016 ◽  
Vol 62 (233) ◽  
pp. 535-551 ◽  
Author(s):  
M. CAPT ◽  
J.-B. BOSSON ◽  
M. FISCHER ◽  
N. MICHELETTI ◽  
C. LAMBIEL
Keyword(s):  
Mass Balance ◽  
Surface Characteristics ◽  
Horizontal Displacement ◽  
Swiss Alps ◽  
Average Mass ◽  
Future Evolution ◽  
Free Zone ◽  
Aerial Photogrammetry ◽  
Glacier System ◽  
Permafrost Environment

AbstractGlacier response to climate forcing can be heterogeneous and complex, depending on glacier system characteristics. This article presents the decadal evolution of the Tsarmine Glacier (Swiss Alps), a very small and heavily debris-covered cirque glacier located in the Alpine periglacial belt. Archival aerial photogrammetry and autocorrelation of orthophotos were used to compute surface elevation, volume and geodetic mass changes, as well as horizontal displacement rates for several periods between 1967 and 2012. A GPR survey allowed us to investigate glacier thickness (15 m mean) and volume (4 × 106 m3) in 2015 and to anticipate its future evolution. Different dynamics occurred in recent decades because of the heterogeneous surface characteristics. The climate-sensitive upper debris-free zone contrasts with the progressively stagnant heavily debris-covered glacier tongue. Between 1967 and 2012, the glacier lost 1/3 of its initial volume (2 × 106 m3). The average mass balance stabilised at ~−0.3 m w.e. a−1 since 1999. Compared with other local glaciers, the Tsarmine Glacier shows a particular decadal behaviour both in time (divergence of mass balance since the 2000s) and space (inverted ablation pattern). This might be explained by the combined influence of debris cover, shadow, snow redistribution and permafrost conditions on this very small glacier.

scholarly journals Climatic Change in a High-Altitude Alpine Area Suggested by the Isotopic Composition Of Cold Basal Glacier Ice

1990 ◽  
Vol 14 ◽  
pp. 168-171 ◽  
Author(s):  
R. Lorrain ◽  
W. Haeberli
Keyword(s):  
Isotopic Composition ◽  
High Altitude ◽  
Temperature Effect ◽  
Climatic Change ◽  
Swiss Alps ◽  
Value Differences ◽  
Water Percolation ◽  
Melt Water ◽  
Glacier Ice ◽  
First Time

For the first time, a cold ice cover of a summit in the central Swiss Alps has been sampled from the surface to the bed for determining its isotopic composition in δD and δ18O. Results of the analyses show a striking decrease of δ-values with depth. The δ-value differences are greater than those explicable by a direct temperature effect, but a substantial increase in melt water percolation through the firn since the formation of the deepest ice layer may explain the situation of this high-altitude ice.

scholarly journals Climatic Change in a High-Altitude Alpine Area Suggested by the Isotopic Composition Of Cold Basal Glacier Ice

1990 ◽  
Vol 14 ◽  
pp. 168-171 ◽  
Author(s):  
R. Lorrain ◽  
W. Haeberli
Keyword(s):  
Isotopic Composition ◽  
High Altitude ◽  
Temperature Effect ◽  
Climatic Change ◽  
Swiss Alps ◽  
Value Differences ◽  
Water Percolation ◽  
Melt Water ◽  
Glacier Ice ◽  
First Time

For the first time, a cold ice cover of a summit in the central Swiss Alps has been sampled from the surface to the bed for determining its isotopic composition in δD and δ18O. Results of the analyses show a striking decrease of δ-values with depth. The δ-value differences are greater than those explicable by a direct temperature effect, but a substantial increase in melt water percolation through the firn since the formation of the deepest ice layer may explain the situation of this high-altitude ice.

scholarly journals Mass balance and recession of Ürümqi glacier No. 1, Tien Shan, China, over the last 45 years

2006 ◽  
Vol 43 ◽  
pp. 214-217 ◽  
Author(s):  
Zhefan Jing ◽  
Keqin Jiao ◽  
Tandong Yao ◽  
Ninglian Wang ◽  
Zhongqin Li
Keyword(s):  
Mass Balance ◽  
Summer Precipitation ◽  
Flow Speed ◽  
Tien Shan ◽  
The Past ◽  
Glacier Melt ◽  
Glacier Ice ◽  
Precipitation Increase ◽  
Summer Temperatures ◽  
Glacier Flow

AbstractObservations of Ürümqi glacier No. 1 at the headwaters of the Ürümqi river, Tien Shan, show remarkable changes between 1959 and 2003. The cumulative mass balance of the glacier is –10 032 mm, equivalent to 11.1 m of glacier ice, or 20% of the glacier volume, showing particular sensitivity to temperature change. The speed of glacier flow has gradually declined, especially since the 1980s. From 1980 to 2003, the flow speed of the east and west branches of the glacier decreased by about 21% and 43%, respectively. The glacier continuously retreated from 1962 to 2003. Its length has decreased by about 180 m (7.5%) and its area has diminished by 0.23 km2 (11.8%). Analyses show that summer precipitation is negatively correlated with mass balance and positively associated with runoff. These relationships are reasonable, as higher precipitation leads to higher runoff and lower glacier melt. On the other hand, summer temperature is negatively correlated with mass balance and positively associated with runoff, as higher temperatures lead to higher glacier melt and thus higher runoff, with summer temperatures controlling mass-balance variation. Over the past 45 years the negative mass balance, caused by higher ablation than accumulation, is associated with precipitation increase and temperature warming over the study area.

scholarly journals Changes in Eurasian glaciation during the past century: glacier mass balance and ice-core evidence

1997 ◽  
Vol 24 ◽  
pp. 283-287 ◽  
Author(s):  
Vladimir N. Mikhalenko
Keyword(s):  
Mass Balance ◽  
Ice Core ◽  
Climatic Conditions ◽  
Tien Shan ◽  
The Arctic ◽  
Past Century ◽  
Glacier Mass Balance ◽  
The Past ◽  
Ice Cap ◽  
Glacier Ice

Glaciers of both the Arctic and mid-latitude mountain systems within Eurasia have retreated intensively during the past century. Measured and reconstructed glacier mass balances show that glacier retreat began around the 1880s. The mean annual mass-balance value for 1880–1990 was −480 mm a−1 for glaciers with maritime climatic conditions, and −140 mm a−1 for continental glaciers. It can be concluded that warming in the Caucasus occurred during at least the last 60 years, according to the distribution of crystal sizes in an ice core from the Dzhantugan firn plateau. Temperatures measured in 1962 at 20 m on the Gregoriev ice cap, Tien Shan, were −4.2°C while in 1990 they were −2°C, a warming of 2.2°C over 28 years. Changes in the isotopic composition of glacier ice during the 20th century indicate recent and continuing warming in different regions of Eurasia. The δ 18O records reveal an enrichment at the Gregoriev ice cap during the last 50 years, while surface temperatures at the Tien Shan meteorological station have increased 0.5°C since 1930.

Sleep in western culture

2018 ◽  
Author(s):  
Roger Ekirch
Keyword(s):  
Nineteenth Century ◽  
Sleep Deprivation ◽  
Industrial Revolution ◽  
Sleep Onset ◽  
Western Culture ◽  
The Past ◽  
Predominant Form ◽  
Artificial Illumination ◽  
Illness Anxiety

Although a universal necessity, sleep, as the past powerfully indicates, is not a biological constant. Before the Industrial Revolution, sleep in western households differed in a variety of respects from that of today. Arising chiefly from a dearth of artificial illumination, the predominant form of sleep was segmented, consisting of two intervals of roughly 3 hours apiece bridged by up to an hour or so of wakefulness. Notwithstanding steps taken by families to preserve the tranquillity of their slumber, the quality of pre-industrial sleep was poor, owing to illness, anxiety, and environmental vexations. Large portions of the labouring population almost certainly suffered from sleep deprivation. Despite the prevalence of sleep-onset insomnia, awakening in the middle of the night was thought normal. Not until the turn of the nineteenth century and sleep’s consolidation did physicians view segmented sleep as a disorder requiring medication.

Effect of Variations in Weight or Normal Acceleration on the Ceiling of Jet-Propelled Aircraft

1955 ◽  
Vol 59 (534) ◽  
pp. 435-437
Author(s):  
P. L. Sutcliffe
Keyword(s):  
High Altitude ◽  
Normal Force ◽  
Control Surface ◽  
Military Aircraft ◽  
Longitudinal Control ◽  
The Past ◽  
Normal Acceleration

The ability to manoeuvre at high altitude has become one of the main requirements in the design of modern military aircraft. Ability to manoeuvre enables the fighter pilot to execute tight turns during the attack on a bomber and the bomber pilot to perform evasive manoeuvres and so make the task of the fighter more difficult.Normally the main manoeuvre considered is the application of increased normal acceleration, or g, and if we assume that (a) there is sufficient pitching power available from the longitudinal control surface to increase the wing incidence to give the necessary increase in normal force, and (b) that the new wing incidence is below the stalling incidence of the wing, then the degree of manoeuvrability available is a function of thrust and drag alone. In the past the manoeuvrability required at a given altitude has been expressed in terms of the rate of climb available at that altitude and thus we have such definitions as “ the 1,000 ft./min. ceiling ” and so on.

scholarly journals First in situ record of decadal glacier mass balance (2003–2014) from the Bhutan Himalaya

2016 ◽  
Vol 57 (71) ◽  
pp. 289-294 ◽  
Author(s):  
Phuntsho Tshering ◽  
Koji Fujita
Keyword(s):  
Mass Balance ◽  
Direct Method ◽  
Eastern Himalaya ◽  
Glacier Mass Balance ◽  
Differential Gps ◽  
Humid Climate ◽  
Equilibrium Line Altitude ◽  
The Past ◽  
Southeastern Tibet

AbstractThis study presents the first decadal mass-balance record of a small debris-free glacier in the Bhutan Himalaya, where few in situ measurements have been reported to date. Since 2003 we have measured the mass balance of Gangju La glacier, which covers an area of 0.3km2 and extends from 4900 to 5200ma.s.l., using both differential GPS surveys (geodetic method) and stake measurements (direct method). The observed mass balance ranged from –1.12 to –2.04mw.e. a–1 between 2003 and 2014. The glacier exhibited much greater mass loss than neighbouring glaciers in the eastern Himalaya and southeastern Tibet, which are expected to be sensitive to climate change due to the monsooninfluenced humid climate. Observed mass-balance profiles suggest that the equilibrium-line altitude has been higher than Gangju La glacier since 2003, implying that the entire glacier has experienced net ablation for at least the past decade.

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