scholarly journals A novel integrated method to describe dust and fine supraglacial debris and their effects on ice albedo: the case study of Forni Glacier, Italian Alps

2014 ◽  
Vol 8 (3) ◽  
pp. 3171-3206 ◽  
Author(s):  
R. S. Azzoni ◽  
A. Senese ◽  
A. Zerboni ◽  
M. Maugeri ◽  
C. Smiraglia ◽  
...  
Keyword(s):  
Black Carbon ◽  
Organic Content ◽  
Glacier Surface ◽  
Integrated Method ◽  
Ice Melt ◽  
Natural Logarithm ◽  
Marked Variability ◽  
Glacier Melting ◽  
Melting Surface ◽  
Debris Coverage

Abstract. We investigated the characteristics of sparse and fine debris coverage at the glacier melting surface and its relation to ice albedo. In spite of the abundant literature dealing with dust and black carbon deposition on glacier accumulation areas (i.e.: on snow and firn), few studies that describe the distribution and properties of fine and discontinuous debris and black carbon at the melting surface of glaciers are available. Furthermore, guidelines are needed to standardize field samplings and lab analyses thus permitting comparisons among different glaciers. We developed a protocol to (i) sample fine and sparse supraglacial debris and dust, (ii) quantify their surface coverage and the covering rate, (iii) describe composition and sedimentological properties, (iv) measure ice albedo and (v) identify the relationship between ice albedo and fine debris coverage. The procedure was tested on the Forni Glacier surface (northern Italy), in summer 2011, 2012 and 2013, when the fine debris and dust presence had marked variability in space and time (along the glacier tongue and from the beginning to the end of summer) thus influencing ice albedo: in particular the natural logarithm of albedo was found to depend on the percentage of glacier surface covered by debris. Debris and dust analyses indicate generally a local origin (from nesting rockwalls) and the organic content was locally high. Nevertheless the finding of some cenospheres suggests an anthropic contribution to the superficial dust as well. Moreover, the effect of liquid precipitation on ice albedo was not negligible, but short lasting (from 1 to 4 day long), thus indicating that also other processes affect ice albedo and ice melt rates and then some attention has to be spent analysing frequency and duration of summer rainfalls for better describing albedo and melt variability.

scholarly journals Estimating ice albedo from fine debris cover quantified by a semi-automatic method: the case study of Forni Glacier, Italian Alps

2016 ◽  
Vol 10 (2) ◽  
pp. 665-679 ◽  
Author(s):  
Roberto Sergio Azzoni ◽  
Antonella Senese ◽  
Andrea Zerboni ◽  
Maurizio Maugeri ◽  
Claudio Smiraglia ◽  
...  
Keyword(s):  
Data Sets ◽  
Alpine Valley ◽  
Natural Logarithm ◽  
Glacier Melting ◽  
Parallel Data ◽  
Sensitivity Tests ◽  
Melting Surface ◽  
D Values ◽  
The Impact ◽  
Debris Coverage

Abstract. In spite of the quite abundant literature focusing on fine debris deposition over glacier accumulation areas, less attention has been paid to the glacier melting surface. Accordingly, we proposed a novel method based on semi-automatic image analysis to estimate ice albedo from fine debris coverage (d). Our procedure was tested on the surface of a wide Alpine valley glacier (the Forni Glacier, Italy), in summer 2011, 2012 and 2013, acquiring parallel data sets of in situ measurements of ice albedo and high-resolution surface images. Analysis of 51 images yielded d values ranging from 0.01 to 0.63 and albedo was found to vary from 0.06 to 0.32. The estimated d values are in a linear relation with the natural logarithm of measured ice albedo (R  =  −0.84). The robustness of our approach in evaluating d was analyzed through five sensitivity tests, and we found that it is largely replicable. On the Forni Glacier, we also quantified a mean debris coverage rate (Cr) equal to 6 g m−2 per day during the ablation season of 2013, thus supporting previous studies that describe ongoing darkening phenomena at Alpine debris-free glaciers surface. In addition to debris coverage, we also considered the impact of water (both from melt and rainfall) as a factor that tunes albedo: meltwater occurs during the central hours of the day, decreasing the albedo due to its lower reflectivity; instead, rainfall causes a subsequent mean daily albedo increase slightly higher than 20 %, although it is short-lasting (from 1 to 4 days).

scholarly journals Change in the Extent of Glaciers and Glacier Runoff in the Chinese Sector of the Ile River Basin between 1962 and 2012

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1668
Author(s):  
Larissa Kogutenko ◽  
Igor Severskiy ◽  
Maria Shahgedanova ◽  
Bigzhang Lin
Keyword(s):  
Early Spring ◽  
Glacier Area ◽  
Index Method ◽  
Glacier Surface ◽  
Vegetative Period ◽  
Ice Melt ◽  
Total Runoff ◽  
Initial Area ◽  
Glacier Runoff ◽  
The 1960S

Change in glacier area in the Kuksu and Kunes river basins, which are tributaries to the internationally important Ile River, were assessed at two different time steps between 1962/63, 1990/93, and 2010/12. Overall, glaciers lost 191.3 ± 16.8 km2 or 36.9 ± 6.5% of the initial area. Glacier wastage intensified in the latter period: While in 1962/63–1990/93 glaciers were losing 0.5% a−1, in 1990/93–2010/12, they were losing 1.2% a−1. Streamflow of the Ile River and its tributaries do not exhibit statistically significant change during the vegetative period between May and September. Positive trends were observed in the Ile flow in autumn, winter, and early spring. By contrast, the calculation of the total runoff from the glacier surface (including snow and ice melt) using temperature-index method and runoff forming due to melting of multiyear ice estimated from changes in glacier volume at different time steps between the 1960s and 2010s, showed that their absolute values and their contribution to total river runoff declined since the 1980s. This change is attributed to a strong reduction in glacier area.

scholarly journals Dark Glacier Surface of Greenland’s Largest Floating Tongue Governed by High Local Deposition of Dust

2020 ◽  
Vol 12 (22) ◽  
pp. 3793
Author(s):  
Angelika Humbert ◽  
Ludwig Schröder ◽  
Timm Schultz ◽  
Ralf Müller ◽  
Niklas Neckel ◽  
...  
Keyword(s):  
Black Carbon ◽  
Laser Scanner ◽  
Greenland Ice Sheet ◽  
Remote Sensing Data ◽  
Mineralogical Composition ◽  
Glacier Surface ◽  
Supraglacial Lakes ◽  
Governing Factor ◽  
Local Deposition ◽  
Sentinel 2

Surface melt, driven by atmospheric temperatures and albedo, is a strong contribution of mass loss of the Greenland Ice Sheet. In the past, black carbon, algae and other light-absorbing impurities were suggested to govern albedo in Greenland’s ablation zone. Here we combine optical (MODIS/Sentinel-2) and radar (Sentinel-1) remote sensing data with airborne radar and laser scanner data, and engage firn modelling to identify the governing factors leading to dark glacier surfaces in Northeast Greenland. After the drainage of supraglacial lakes, the former lake ground is a clean surface represented by a high reflectance in Sentinel-2 data and aerial photography. These bright spots move with the ice flow and darken by more than 20% over only two years. In contrast, sites further inland do not exhibit this effect. This finding suggests that local deposition of dust, rather than black carbon or cryoconite formation, is the governing factor of albedo of fast-moving outlet glaciers. This is in agreement with a previous field study in the area which finds the mineralogical composition and grain size of the dust comparable with that of the surrounding soils.

Glacier surface elevation changes in Rongbuk Catchment of the Central Himalayas in the last four decades

2020 ◽  
Author(s):  
Qinghua Ye ◽  
Wei Nie ◽  
Yimin Chen ◽  
Gang Li ◽  
lide Tian ◽  
...  
Keyword(s):  
Climate Modeling ◽  
Melting Rate ◽  
Surface Elevation ◽  
High Mountain ◽  
Glacier Surface ◽  
Important Indicator ◽  
Central Himalayas ◽  
Glacier Melting ◽  
Elevation Changes ◽  
Thinning Rate

<p>Glaciers in the central Himalayas are important water resources for the downstream habitants, and accelerating melting of the high mountain glaciers speed up with continuous warming. We summerized the geodetic glacier surface elevation changes (Dh) by 6 data sets at different time periods during 1974-2016 in RongbukCatchment(RC) on the northern slope of Mt. Qomolangma (Mt. Everest) in the Central Himalayas. The result showed that glacier Dh varied with altitude and time, from -0.29 ± 0.03m a<sup>-1</sup> in 1974-2000, to -0.47 ±0.24 m a<sup>-1</sup> in 1974-2006,and -0.48 ±0.16 m a<sup>-1</sup> in 1974-2012. Dh increased to -0.60 ± 0.20 m a<sup>-1</sup> in 2000-2012, then decreased to-0.46 ± 0.24 m a<sup>-1</sup> in 2000-2014, and by -0.49 ± 0.08 m a<sup>-1</sup> in 2000-2016, showing a diverse rate being up - down- a little up. However, it generally presented a similar glacier thinning rate by -0.46~-0.49 m a<sup>-1</sup> in the last four decades since 1970s in RC according to Dh<sub>1974-2006</sub>, Dh<sub>1974-2012</sub>, Dh<sub>2000-2014</sub>, and Dh<sub>2000-2016</sub>. Local meteorological observations revealed that, to a first order, the glacier thinning rate was kept the same pace with the number of annual melting days (MD). In spite of the obviously arising summer air temperature (T<sub>S</sub>) in 2000-2014, a slowdown glacier melting rate by -391 mm w.e.a<sup>-1</sup> occurred in 2000-2014 because of less melting days with more precipitation and less annual mean temperature(T<sub>m</sub>). It shows that MD is another important indicator and controlling factor to evaluate or to estimate glacier melting trend, especially in hydrological or climate modeling.</p>

Glacier Melting, Disaster and Awareness Programme

2016 ◽  
Vol 8 (02) ◽  
pp. 131-138
Author(s):  
Bharat Raj Singh ◽  
Amar Bahadur Singh
Keyword(s):  
Agricultural Soils ◽  
Ice Sheets ◽  
Storm Surges ◽  
Past Century ◽  
Sea Levels ◽  
Ice Caps ◽  
Ice Melt ◽  
The Past ◽  
Glacier Melting ◽  
Awareness Programme

Large ice formations, like glaciers and the polar ice caps, naturally melt back a bit each summer. But, in the winter, snows, made primarily from evaporated seawater, are generally sufficient to balance out the melting. Recently, though, persistently higher temperatures caused by global warming have led to greaterthan- average summer melting as well as diminished snowfall due to later winters and earlier springs. This imbalance results in a significant net gain in runoff versus evaporation for the ocean, causing sea levels to rise. Satellite measurements tell us that over the past century, the Global Mean Sea Level (GMSL) has risen by 4 to 8 inches (10 to 20 centimeters). However, the annual rate of rise over the past 20 years has been 0.13 inches (3.2 millimeters) a year, roughly twice the average speed of the preceding 80 years. As with glaciers and the ice caps, increased heat is causing the massive ice sheets, that cover Greenland and Antarctica to melt at an accelerated pace. Scientists also believe ice-melt water from above and seawater from below is seeping beneath Greenland's and West Antarctica's ice sheets, effectively lubricating ice streams and causing them to move more quickly into the sea. Moreover, higher sea temperatures are causing the massive ice shelves that extend out from Antarctica to melt from below, weaken, and break off. When sea levels rise rapidly, as they have been doing, even a small increase can have devastating effect on coastal habitats. As seawater reaches farther inland, it can cause destructive erosion, flooding of wetlands, contamination of aquifers and agricultural soils, and lost habitat for fish, birds, and plants. When large storms hit land, higher sea levels mean bigger, more powerful storm surges that can strip away everything in their path. In addition, hundreds of millions of people live in areas that will become increasingly vulnerable to flooding. Higher sea levels would force them to abandon their homes and relocate. Low-lying islands could be submerged completely. Thus, it needs launching of serious awareness programme through print media, electronic media to curb the glacier melting by reducing heavy consumption of hydrocarbon and focus on zero pollution researches to develop energy production alternatives.

scholarly journals Summer Mass Balance and Surface Velocity Derived by Unmanned Aerial Vehicle on Debris-Covered Region of Baishui River Glacier No. 1, Yulong Snow Mountain

2020 ◽  
Vol 12 (20) ◽  
pp. 3280 ◽  
Author(s):  
Yanjun Che ◽  
Shijin Wang ◽  
Shuhua Yi ◽  
Yanqiang Wei ◽  
Yancong Cai
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Global Climate ◽  
Surface Velocity ◽  
Dynamic Features ◽  
Glacier Surface ◽  
Glacier Melting ◽  
Western Kunlun ◽  
The Mean ◽  
Yulong Snow Mountain

Glacier retreat is a common phenomenon in the Qinghai-Tibetan Plateau (QTP) with global warming during the past several decades, except for several mountains, such as the glaciers in the Karakoram and the western Kunlun Mountains. The dynamic nature of glaciers significantly influences the hydrologic, geologic, and ecological systems in the mountain regions. The sensitivity and dynamic response to climate change make glaciers excellent indicators of regional and global climate change, such as glacier melting and retreat with the rise of local air temperature. Long-term monitoring of glacier change is important to understand and assess past, current, and possible future climate environments. Some glacier surfaces are safe and accessible by foot, and are monitored using mass balance stakes and snow pits. Meanwhile, some glaciers with inaccessible termini may be surveyed using satellite remote images and Unmanned Aerial Vehicles (UAVs). Those inaccessible glaciers are generally covered by debris in the southeast QTP, which is hardly accessible due to the wide distribution of crevasses and cliffs. In this paper, we used the UAV to monitor the dynamic features of mass balance and velocity of the debris-covered region of Baishui River Glacier No. 1 (BRG1) on the Yulong Snow Mountain (YSM), Southeast QTP. We obtained the Orthomosaic and DEM with a high resolution of 0.10 m on 20 May and 22 September 2018, respectively. The comparison showed that the elevation of the debris-covered region of the BRG1 decreased by 6.58 m ± 3.70 m on average, and the mean mass balance was −5.92 m w.e. ± 3.33 m w.e. during the summer, correspondingly. The mean displacement of debris-covered glacier surface was 18.30 m ± 6.27 m, that is, the mean daily velocity was 0.14 m/d ± 0.05 m/d during the summer. In addition, the UAV images not only revealed the different patterns of glacier melting and displacement but also captured the phenomena of mass loss due to ice avalanches at the glacier front and the development of large crevasses. This study provides a feasible method for understanding the dynamic features of global debris-covered glaciers which are inaccessible and unobservable by other means.

scholarly journals Black carbon record based on a shallow Himalayan ice core and its climatic implications

2008 ◽  
Vol 8 (5) ◽  
pp. 1343-1352 ◽  
Author(s):  
J. Ming ◽  
H. Cachier ◽  
C. Xiao ◽  
D. Qin ◽  
S. Kang ◽  
...  
Keyword(s):  
Black Carbon ◽  
Radiative Forcing ◽  
Trajectory Analysis ◽  
Ice Core ◽  
Historical Record ◽  
The Tibetan Plateau ◽  
Hysplit Model ◽  
The Past ◽  
Glacier Melting ◽  
Increasing Trend

Abstract. A continuous measurement for black carbon (hereafter "BC") in a 40 m shallow ice core retrieved from the East Rongbuk Glacier (hereafter "ERG") in the northeast saddle of Mt. Qomolangma (Everest) provided the first historical record of BC deposition during the past ~50 yrs in the high Himalyas. Apparent increasing trend (smooth average) of BC concentrations was revealed since the mid-1990s. Seasonal variability of BC concentrations in the ice core indicated higher concentrations in monsoon seasons than those in non-monsoon seasons. Backward air trajectory analysis by the HYSPLIT model indicated that South Asia's BC emissions had significant impacts on the BC deposition in the Mt. Qomolangma (Everest) region. The estimated average atmospheric BC concentration in the region was about 80 ng m−3 during 1951–2001. And it was suggested BC emitted from South Asia could penetrate into the Tibetan Plateau by climbing over the elevated Himalayas. A significant increasing trend of the radiative forcing simulated by the SNICAR model appeared since 1990, which even exceeded 4.5 W m−2 in the summer of 2001. It was suggested that this amplitudes of BC concentrations in the atmosphere over the Himalayas and consequently in the ice in the glaciers could not be neglected when assessing the dual warming effects on glacier melting in the Himalayas.

scholarly journals Amazonian BC Contribution to the Vallunaraju Glacier Surface Melt

2020 ◽  
Author(s):  
Wilmer Sánchez ◽  
Carl Schmitt ◽  
Alexzander Santiago ◽  
Gerles Medina
Keyword(s):  
Black Carbon ◽  
Forest Fires ◽  
Radiative Forcing ◽  
Dry Season ◽  
Decision Makers ◽  
Ablation Zone ◽  
Wet Season ◽  
Glacier Surface ◽  
Glacial Retreat

The role of Black Carbon (BC) as a contributor to glacial retreat is of particular interest to the scientific community and decision makers, due to its impact on snow albedo and glacier melt. In this study, a thermal-optical instrument (LAHM) was used to measure effective Black Carbon (eBC) in a series of surface snow samples collected from the Vallunaraju glacier, Cordillera Blanca, between April 2019 and May 2020. The time series obtained indicates a marked seasonal variability of eBC with maximum concentrations during the dry season and dramatic decrease during the wet season. The concentrations detected ranged between a minimum of 3.73 ng/g and 4.23 ng/g during the wet season and a maximum of 214.13 ng/g and 181.60 ng/g during the dry season, in the accumulation and ablation zone. Using SNICAR model, the reduction of albedo was estimated at 6.36% and 6.60% during the dry season and 0.68% and 0.95% during the wet season, which represents an average radiative forcing of 4.52 ± 1.84 W/m2 and 4.69 ± 1.59 W/m2 in the accumulation zone, and 0.49 ± 0.27 W/m2 and 0.68 ± 0.43 W/m2 in the ablation zone. The melting of snow due to the eBC translates into 80.18 ± 37.30 kg/m2 and 83.16 ± 32.75 kg/m2 during the dry season, and 7.91 ± 4.29 kg/m2 and 10.85 ± 6.62 kg/m2 during the wet season, in the accumulation and ablation zones, respectively. Finally, the HYSPLIT trajectory assessment shows that aerosols predominate in the Amazon rainforest, especially when forest fires are most abundant according to VIIRS images.

scholarly journals Impacts of black carbon and mineral dust on radiative forcing and glacier melting during summer in the Qilian Mountains, northeastern Tibetan Plateau

2016 ◽  
Author(s):  
Yang Li ◽  
Jizu Chen ◽  
Shichang Kang ◽  
Chaoliu Li ◽  
Bin Qu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Black Carbon ◽  
Radiative Forcing ◽  
Mineral Dust ◽  
Qilian Mountains ◽  
Radiation Balance ◽  
In Situ Observation ◽  
Observation Data ◽  
The Tibetan Plateau ◽  
Glacier Melting

Abstract. Black carbon (BC) and mineral dust (MD), the most important compositions of light absorbing particles (LAPs), significantly reduce the albedo of glaciers and thus accelerate their melting. In order to investigate the impacts of BC and MD on the glacier radiation balance and ablation, a total of 92 surface snow/ice samples were collected along different elevations from 4300–4950 m a.s.l. on Laohugou glacier No. 12 (LHG, 39°10'–35' N, 96°10'–35' E), located at Qilian Mountains, northeastern margin of the Tibetan Plateau (TP), during summer of 2013 and 2014. A thermal-optical method was employed to detect the BC (EC – element carbon) concentrations in snow/ice samples. The results showed that BC and MD concentrations were much lower in snow than those in ice, and gradually declined with increasing elevation. The effects of BC and MD on albedo reduction at different melting conditions were identified with the SNow ICe Aerosol Radiative (SNICAR) model initiated by in-situ observation data. The sensitivity analysis showed that BC had a stronger impact on albedo reduction than MD on this glacier. The impacts of BC represented around 45 % of albedo reduction while the contribution of MD was 35 % when the glacier surface presented as superimposed ice and experienced intensive melting. During summer, when the surface was covered by snow, BC and MD contributed for 15 % and 9 % respectively. On average, the radiative forcing (RF) caused by BC in the snow/ice, more than MD, was 41.6 ± 37.0 W m−2. Meanwhile, compared to glacier melting in summer of 2013 and 2014 (409 mm w.e. and 366 mm w.e., respectively) calculated using the surface energy-mass balance model, contributions of BC and MD were less than 37 % and 32 % respectively of summer melting, while MD and BC together contributed a maximum of 61 %. This study provided the baseline information on BC and MD concentrations in glaciers of the northeastern TP and their contributions in glacier melting during summer.

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