scholarly journals Seasonal variation of ice melting on varying layers of debris of Lirung Glacier, Langtang Valley, Nepal

2015 ◽  
Vol 368 ◽  
pp. 21-26 ◽  
Author(s):  
M. B. Chand ◽  
R. B. Kayastha ◽  
A. Parajuli ◽  
P. K. Mool
Keyword(s):  
Energy Source ◽  
Seasonal Variation ◽  
Monsoon Season ◽  
Net Radiation ◽  
Ice Melting ◽  
Ice Melt ◽  
Debris Cover ◽  
Glacier Ice ◽  
Seasonal Melting ◽  
Langtang Valley

Abstract. Glaciers in the Himalayan region are often covered by extensive debris cover in ablation areas, hence it is essential to assess the effect of debris on glacier ice melt. Seasonal melting of ice beneath different thicknesses of debris on Lirung Glacier in Langtang Valley, Nepal, was studied during three seasons of 2013–14. The melting rates of ice under 5 cm debris thickness are 3.52, 0.09, and 0.85 cm d−1 during the monsoon, winter and pre-monsoon season, respectively. Maximum melting is observed in dirty ice (0.3 cm debris thickness) and the rate decreases with the increase of debris thickness. The energy balance calculations on dirty ice and at 40 cm debris thickness show that the main energy source of ablation is net radiation. The major finding from this study is that the maximum melting occurs during the monsoon season than rest of the seasons.

scholarly journals Influence of a Debris Layer on the Melting of Ice on Lirung Glacier, Langtang Valley, Rasuwa, Nepal

2016 ◽  
Vol 9 (1) ◽  
pp. 95-108 ◽  
Author(s):  
Sonika Shahi ◽  
Rijan B. Kayastha
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Sensible Heat Flux ◽  
Ablation Rate ◽  
Balance Model ◽  
Average Value ◽  
Ice Melt ◽  
Debris Cover ◽  
Glacier Ice ◽  
Langtang Valley

This paper provides information about the variation of ice ablation rate underneath the highly heterogeneous debris layer on Lirung Glacier in Langtang Valley, Rasuwa district, Nepal. Ice melt under a debris cover has been commonly modelled using two approaches: physically-based energy-balance models and more empirical temperature-index models. Energy Balance Model (EMB) was used at the point scale to calculate melt under a debris-covered glacier. Because of the high heterogeneity of the surface layer, the ablation rate varies throughout the glacier. The average value of thermal resistance (R) in association with the meteorological variables is found to be sufficient enough to give the consistent value of ablation of glacier ice underneath the debris layer. Solar radiation is the only dominant heat flux which contributes to melting of ice under the debris cover with a little contribution of sensible heat flux in dawn because of the heat storage phenomenon of the debris. In spite of several simplifications, the model performs well and modelled melt rates give a good match to observed melt rates. Thus for accurate distributed melt modelling at different locations of the debris covered glacier it is important to considered the effects of both the external variables and the physical properties of the debris material, which in turn gives estimates of the amount of discharge from the glacier, an important component of the local water resources.

Population and Group Size of Cheer Pheasant Catreus Wallichii in Pokhari Valley, Garhwal Himalaya, India

2021 ◽  
Vol 9 (VII) ◽  
pp. 3503-3505
Author(s):  
Manish Kukreti
Keyword(s):  
Population Dynamics ◽  
Seasonal Variation ◽  
Group Size ◽  
Monsoon Season ◽  
Garhwal Himalaya ◽  
Spring Season ◽  
Maximum Value ◽  
Minimum Group

Present paper reports population dynamics of Cheer pheasant Catreus wallichii in Pokhari valley, Garhwal Himalaya during January 2019 to December 2019. A total of 405 individuals with 145 groups were recorded. Overall individuals per sighting and group size (3.88±0.51 and 3.40±0.45) were also recorded during the study period respectively. Maximum value of individuals per sighting and group size were recorded in months of July and November (6.13±0.76 and 7.32±0.97), while minimum were recorded in May and April (1.75±0.27 and 1.17±0.26). Seasonal variation was also observed in population and group size. Maximum value of individual per sighting was recorded during the Monsoon season and minimum were recorded in spring season. While maximum and minimum group size were recorded in winter and spring Season.

scholarly journals Glacial debris cover and melt water production for glaciers in the Altay, Russia

2011 ◽  
Vol 5 (1) ◽  
pp. 401-430 ◽  
Author(s):  
C. Mayer ◽  
A. Lambrecht ◽  
W. Hagg ◽  
Y. Narozhny
Keyword(s):  
Ice Melt ◽  
The North ◽  
Altay Mountains ◽  
Digital Elevation ◽  
Glacier Runoff ◽  
Debris Cover ◽  
Continuous Mass ◽  
Different Depths ◽  
The 1960S ◽  
Elevation Model

Abstract. Glaciers are important water storages on a seasonal and long-term time scale. Where high mountains are surrounded by arid lowlands, glacier runoff is an important source of water during the growing season. This situation can be found in the Altay mountains in Southern Siberia, where the recent glacierization of >700 km2 is subject to continuous mass loss, even though the shrinking is comparably slow. The glacier retreat is accompanied by an extension of supra-glacial moraine, which itself strongly influences ablation rates. To quantify these effects, the spatial evolution of debris cover since 1952 was analysed for three glaciers in the North Chuya Ridge using satellite and airborne imagery. In summer 2007, an ablation experiment was carried out on debris covered parts of Maliy Aktru glacier. Thermistors in different depths within the moraine provided data to calculate thermal resistance of the debris. A set of ablation stakes was installed at locations with differing debris thickness and observed regularly throughout the entire melt season. Air temperature from an AWS was used to calculate degree day factors in dependence of the debris thickness. To take into account the shading effect of surrounding walls and peaks, the potential solar radiation and its evolution throughout the summer was determined from a digital elevation model. This allows us to extrapolate our measurements from Maliy Aktru to the other two glaciers of the Aktru basin and to estimate basin melt rates. In addition accumulated ice melt was derived for 12 glaciers in the North Chuya Range. Changes in summer runoff from the 1960s are compared to the results from our melt model and the evolution of debris cover is analysed in respect to the melt activity.

Effect of Prewetting Brines and Mixing on Ice-Melting Rate of Salt at Cold Temperatures: New Tracer Dilution Method

2017 ◽  
Vol 2613 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Scott Koefod
Keyword(s):  
Freezing Point ◽  
Melting Rate ◽  
Test Method ◽  
Dilution Method ◽  
Ice Melting ◽  
Cold Temperatures ◽  
Ice Melt ◽  
Solid Salt ◽  
Different Temperatures ◽  
Tracer Dilution

A novel test method has been developed to measure the ice-melting rate of deicers. The ice-melting rates of prewetted salt were determined by measuring the change in the concentration of chloride (Cl−) or magnesium or calcium cations (Mg2+ or Ca2+, respectively) in the ice melt as tracers. The method is substantially more precise than the SHRP H205.1 standard and has the further advantage of measuring ice-melting and salt dissolution rates simultaneously. Brines were preequilibrated with ice at −19.3°C (−2.7°F) and blended with solid salt to determine the effect of different prewetting brines on the ice-melting rate of the solid salt component only. The measured equilibrium ice-melting capacity of sodium chloride (NaCl) agreed well with the theoretical value calculated from the NaCl freezing point curve. Under a condition of no mixing, solid salt yielded 0.87% of its total available ice-melting capacity after 60 min when wetted with NaCl brine and 9.7% when wetted with calcium chloride (CaCl2) brine. Mixing raised the yield of ice melt to 27.1% and 50.5% after 60 min when wet with NaCl and CaCl2 brines, respectively. The CaCl2 brine was slightly more effective than the magnesium chloride (MgCl2) brine at enhancing the ice-melting rate of salt. The test method promises to be a useful tool for permitting a more precise optimization of prewetting brine composition, concentration, and brine-to-salt ratio at different temperatures. The method may also permit better determination of the cost-effectiveness of different prewetting strategies and provide deeper insights into the mechanism of chemical ice melting.

scholarly journals Multiple remote-sensing assessment of the catastrophic collapse in Langtang Valley induced by the 2015 Gorkha earthquake

2017 ◽  
Vol 17 (11) ◽  
pp. 1907-1921 ◽  
Author(s):  
Hiroto Nagai ◽  
Manabu Watanabe ◽  
Naoya Tomii ◽  
Takeo Tadono ◽  
Shinichi Suzuki
Keyword(s):  
Monsoon Season ◽  
Deposition Process ◽  
Visual Interpretation ◽  
Gorkha Earthquake ◽  
Water Stream ◽  
2015 Gorkha Earthquake ◽  
Himalayan Mountain ◽  
Hazard Process ◽  
Langtang Valley

Abstract. The main shock of the 2015 Gorkha Earthquake in Nepal induced numerous avalanches, rockfalls, and landslides in Himalayan mountain regions. A major village in the Langtang Valley was destroyed and numerous people were victims of a catastrophic avalanche event, which consisted of snow, ice, rock, and blast wind. Understanding the hazard process mainly depends on limited witness accounts, interviews, and an in situ survey after a monsoon season. To record the immediate situation and to understand the deposition process, we performed an assessment by means of satellite-based observations carried out no later than 2 weeks after the event. The avalanche-induced sediment deposition was delineated with the calculation of decreasing coherence and visual interpretation of amplitude images acquired from the Phased Array-type L-band Synthetic Aperture Radar-2 (PALSAR-2). These outline areas are highly consistent with that delineated from a high-resolution optical image of WorldView-3 (WV-3). The delineated sediment areas were estimated as 0.63 km2 (PALSAR-2 coherence calculation), 0.73 km2 (PALSAR-2 visual interpretation), and 0.88 km2 (WV-3). In the WV-3 image, surface features were classified into 10 groups. Our analysis suggests that the avalanche event contained a sequence of (1) a fast splashing body with an air blast, (2) a huge, flowing muddy mass, (3) less mass flowing from another source, (4) a smaller amount of splashing and flowing mass, and (5) splashing mass without flowing on the east and west sides. By means of satellite-derived pre- and post-event digital surface models, differences in the surface altitudes of the collapse events estimated the total volume of the sediments as 5.51 ± 0.09  ×  106 m3, the largest mass of which are distributed along the river floor and a tributary water stream. These findings contribute to detailed numerical simulation of the avalanche sequences and source identification; furthermore, altitude measurements after ice and snow melting would reveal a contained volume of melting ice and snow.

Interactive effect of nitrogen nutrition, nitrate reduction and seasonal variation on oxalate synthesis in leaves of Napier-bajra hybrid (Pennisetum purpureum × P. glaucum)

2019 ◽  
Vol 70 (8) ◽  
pp. 669
Author(s):  
Meenakshi Goyal ◽  
Rupinder Kaur
Keyword(s):  
Seasonal Variation ◽  
Nitrogen Nutrition ◽  
Monsoon Season ◽  
Block Design ◽  
Interactive Effect ◽  
Urinary Calculi ◽  
Positive Association ◽  
Pennisetum Purpureum ◽  
N Nutrition ◽  
Oxalate Synthesis

Oxalate may cause hypocalcaemia or formation of urinary calculi in animals with prolonged grazing of Napier grass (Pennisetum purpureum) × pearl millet (bajra, P. glaucum) hybrid (NBH). We investigated the influence of nitrate metabolism, nitrogen (N) nutrition, N forms and seasonal variation on oxalate accumulation in leaves of NBH in a field experiment in Ludhiana, India. The experiment was a randomised block design with three N sources (nitrate, amide and ammonium), three application rates (50, 75 and 100 kg N/ha), four seasons (summer, monsoon, autumn, pre-winter) and three replicates. Applied N nutrition induced oxalate synthesis and activities of nitrate reductase (NR) and nitrite reductase (NiR) enzymes. A positive association of N nutrition with both oxalate accumulation and nitrate-reducing enzymes was found. Nitrate-N increased oxalate accumulation and NiR activity more than ammonium and amide. A differential effect of seasons on NR and NiR activities, as well as on oxalate accumulation, was observed. Among different harvest seasons, NR and NiR activities were positively associated with oxalate accumulation in summer and the monsoon season. These results suggest that N fertilisation, particularly in nitrate form, is associated with upregulation of nitrate-reducing enzymes, leading to oxalate accumulation in NBH leaves.

scholarly journals Supraglacial Debris of G2 Glacier in Hidden Valley, Mukut Himal, Nepal

1979 ◽  
Vol 22 (87) ◽  
pp. 273-283 ◽  
Author(s):  
M. Nakawo
Keyword(s):  
Particle Size ◽  
Monsoon Season ◽  
Simple Relation ◽  
Laboratory Analysis ◽  
Field Investigations ◽  
Hidden Valley ◽  
Glacier Ice ◽  
Glacier Flow

AbstractField investigations of supraglacial debris were carried out during the monsoon season in 1974 on G2 glacier near Tukche Peak in Hidden Valley, Mukut Himal, Nepal. The thickness of the debris layer was observed to increase down-glacier. Laboratory analysis, however, showed a decrease in particle size in the same direction. This decrease is explained in terms of mixing of particles contained in glacier ice with the original debris as melting proceeds. A simple relation between debris mass and glacier flow is introduced to explain the observed results.

scholarly journals Artificially Induced Thermokarst in Active Glacier Ice: An Example from North-West British Columbia, Canada

1977 ◽  
Vol 18 (80) ◽  
pp. 437-444
Author(s):  
N. Eyles ◽  
R. J. Rogerson
Keyword(s):  
Waste Water ◽  
British Columbia ◽  
Review Of The Literature ◽  
North West ◽  
Ice Melt ◽  
Basal Ice ◽  
Glacier Ice

AbstractWarm waste water, at 30°C, has been discharged from a copper concentrater on to the active terminal ice of Berendon Glacier, British Columbia, since 1970. As a result, rapid basal ice melt causes the formation of caverns and subsequent collapse features referred to as glacier thermokarst. A review of the literature reveals that such features have been described elsewhere from active ice, and the usual conditions assumed for the development of glacier thermokarst (stagnant, heavily debris-covered ice) should be redefined to include these examples.

scholarly journals Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacier region of the southeastern Tibetan Plateau

2018 ◽  
Vol 18 (9) ◽  
pp. 6441-6460 ◽  
Author(s):  
Hewen Niu ◽  
Shichang Kang ◽  
Hailong Wang ◽  
Rudong Zhang ◽  
Xixi Lu ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
East Asia ◽  
Climate Model ◽  
Monsoon Season ◽  
Photochemical Reactions ◽  
Carbonaceous Aerosol ◽  
Carbonaceous Aerosols ◽  
Near Surface ◽  
Post Monsoon ◽  
Post Monsoon Season

Abstract. Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51±0.93 and 2.57±1.32 µg m−3, respectively. Although the annual mean OC ∕ EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 ma.s.l.) of Mt. Yulong. Strong photochemical reactions and local tourism activities were likely the main factors inducing high OC ∕ EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m2 g−1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol–climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50 %) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.

scholarly journals Multi-decadal mass loss of glaciers in the Everest area (Nepal Himalaya) derived from stereo imagery

2011 ◽  
Vol 5 (2) ◽  
pp. 349-358 ◽  
Author(s):  
T. Bolch ◽  
T. Pieczonka ◽  
D. I. Benn
Keyword(s):  
Time Series ◽  
Mass Loss ◽  
Mass Balance ◽  
Aerial Images ◽  
Glacier Mass Balance ◽  
Ice Melt ◽  
Debris Cover ◽  
Stereo Imagery ◽  
Glacier Velocity ◽  
The Himalaya

Abstract. Mass loss of Himalayan glaciers has wide-ranging consequences such as changing runoff distribution, sea level rise and an increasing risk of glacial lake outburst floods (GLOFs). The assessment of the regional and global impact of glacier changes in the Himalaya is, however, hampered by a lack of mass balance data for most of the range. Multi-temporal digital terrain models (DTMs) allow glacier mass balance to be calculated. Here, we present a time series of mass changes for ten glaciers covering an area of about 50 km2 south and west of Mt. Everest, Nepal, using stereo Corona spy imagery (years 1962 and 1970), aerial images and recent high resolution satellite data (Cartosat-1). This is the longest time series of mass changes in the Himalaya. We reveal that the glaciers have been significantly losing mass since at least 1970, despite thick debris cover. The specific mass loss for 1970–2007 is 0.32 ± 0.08 m w.e. a−1, however, not higher than the global average. Comparisons of the recent DTMs with earlier time periods indicate an accelerated mass loss. This is, however, hardly statistically significant due to high uncertainty, especially of the lower resolution ASTER DTM. The characteristics of surface lowering can be explained by spatial variations of glacier velocity, the thickness of the debris-cover, and ice melt due to exposed ice cliffs and ponds.

Sign in / Sign up

Export Citation Format

Share Document