scholarly journals Understanding the interrelationships among mass balance, meteorology, discharge and surface velocity on Chhota Shigri Glacier over 2002–2019 using in situ measurements

2020 ◽  
Vol 66 (259) ◽  
pp. 727-741 ◽  
Author(s):  
Arindan Mandal ◽  
Alagappan Ramanathan ◽  
Mohd. Farooq Azam ◽  
Thupstan Angchuk ◽  
Mohd Soheb ◽  
...  
Keyword(s):  
Mass Balance ◽  
Surface Velocity ◽  
Chhota Shigri Glacier ◽  
Himalayan Glaciers ◽  
Ice Velocity ◽  
Long Term Observation ◽  
Surface Ice ◽  
Substantial Change

AbstractThe Himalayan glaciers contribute significantly to regional water resources. However, limited field observations restrict our understanding of glacier dynamics and behaviour. Here, we investigated the long-term in situ mass balance, meteorology, ice velocity and discharge of the Chhota Shigri Glacier. The mean annual glacier-wide mass balance was negative, −0.46 ± 0.40 m w.e. a−1 for the period 2002–2019 corresponding to a cumulative wastage of −7.87 m w.e. Winter mass balance was 1.15 m w.e. a−1 and summer mass balance was −1.35 m w.e. a−1 over 2009–2019. Surface ice velocity has decreased on average by 25–42% in the lower and middle ablation zone (below 4700 m a.s.l.) since 2003; however, no substantial change was observed at higher altitudes. The decrease in velocity suggests that the glacier is adjusting its flow in response to negative mass balance. The summer discharge begins to rise from May and peaks in July, with a contribution of 43%, followed by 38% and 19% in August and September, respectively. The discharge pattern closely follows the air temperature. The long-term observation on the ‘Chhota Shigri – a benchmark glacier’, shows a mass wastage which corresponds to the slowdown of the glacier in the past two decades.

Interrelationships among mass balance, meteorology, discharge, and surface velocity on Chhota Shigri Glacier over 2002-2019 using in-situ measurements

2021 ◽  
Author(s):  
Ramanathan Alagappan(AL) ◽  
Arindan Mandal ◽  
Azam Farooq Mohd ◽  
Thupstan Angchuk ◽  
Soheb Mohd ◽  
...  
Keyword(s):  
Mass Balance ◽  
In Situ Measurements ◽  
Surface Velocity ◽  
The Past ◽  
Chhota Shigri Glacier ◽  
Ice Velocity ◽  
Long Term Observation ◽  
Surface Ice

<p>Interrelationships among mass balance, meteorology, discharge, and surface velocity on Chhota Shigri Glacier over 2002-2019 using in-situ measurements</p><p> </p><p> </p><p>Arindan MANDAL<sup>1</sup>, AL. RAMANATHAN<sup>1*</sup>, Mohd. Farooq AZAM<sup>2</sup>, Thupstan ANGCHUK<sup>1</sup>, Mohd. SOHEB<sup>1</sup>, Naveen KUMAR<sup>1</sup>, Jose George POTTAKKAL<sup>3</sup>, Sarvagya VATSAL<sup>1</sup>, Somdutta MISHRA<sup>1</sup>, Virendra Bahadur SINGH<sup>1,4</sup></p><p><sup> </sup></p><p><sup>*</sup>Corresponding author email: [email protected]</p><p>The Himalayan glaciers contribute significantly to regional water resources. However, limited field observations restrict our understanding of glacier dynamics and behavior. Here, we investigated the long-term in-situ mass balance, meteorology, ice velocity, and discharge of the Chhota Shigri Glacier over the past two decades. With 17 years of uninterrupted glacier-wide mass balance datasets, Chhota Shigri Glacier is one of the most studied glaciers in the Hindu-Kush Himalayan region in terms of mass balance record. The mean annual glacier-wide mass balance was negative, -0.46±0.40 m w.e. a<sup>-1</sup> during 2002-2019 corresponding to a cumulative wastage of about -8 m w.e. Mean winter mass balance was 1.15 m w.e. a<sup>-1</sup> and summer mass balance was -1.35 m w.e. a<sup>-1 </sup>over 2009-2019. Surface ice velocity has decreased on average by 25-42% in the lower and middle ablation zone (below 4700 m a.s.l.) since 2003; however, no substantial change was observed at higher altitudes. The decrease in velocity suggests that the glacier is adjusting its flow in response to negative mass balance. The summer discharge begins to rise from May and peaks in July, with a contribution of 43%, followed by 38% and 19% in August and September, respectively. The discharge pattern closely follows the air temperature. The long-term observation on the Chhota Shigri — a benchmark — glacier, shows a mass wastage that corresponds to the glacier’s slowdown in the past two decades.</p><p> </p><p> </p>

scholarly journals Four years of mass balance on Chhota Shigri Glacier, Himachal Pradesh, India, a new benchmark glacier in the western Himalaya

2007 ◽  
Vol 53 (183) ◽  
pp. 603-611 ◽  
Author(s):  
Patrick Wagnon ◽  
Anurag Linda ◽  
Yves Arnaud ◽  
Rajesh Kumar ◽  
Parmanand Sharma ◽  
...  
Keyword(s):  
Mass Balance ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Western Himalaya ◽  
Vertical Gradient ◽  
Himachal Pradesh ◽  
Surface Velocity ◽  
Equilibrium Line Altitude ◽  
Chhota Shigri Glacier ◽  
Himalayan Glaciers

Little is known about the Himalayan glaciers, although they are of particular interest in terms of future water supply, regional climate change and sea-level rise. In 2002, a long-term monitoring programme was started on Chhota Shigri Glacier (32.2° N, 77.5° E; 15.7 km2, 6263–4050 ma.s.l., 9 km long) located in Lahaul and Spiti Valley, Himachal Pradesh, India. This glacier lies in the monsoon–arid transition zone (western Himalaya) which is alternately influenced by Asian monsoon in summer and the mid-latitude westerlies in winter. Here we present the results of a 4 year study of mass balance and surface velocity. Overall specific mass balances are mostly negative during the study period and vary from a minimum value of –1.4 m w.e. in 2002/03 and 2005/06 (equilibrium-line altitude (ELA) ∼5180 m a.s.l.) to a maximum value of +0.1 m w.e. in 2004/05 (ELA 4855 m a.s.l.). Chhota Shigri Glacier seems similar to mid-latitude glaciers, with an ablation season limited to the summer months and a mean vertical gradient of mass balance in the ablation zone (debris-free part) of 0.7mw.e.(100 m)–1, similar to those reported in the Alps. Mass balance is strongly dependent on debris cover, exposure and the shading effect of surrounding steep slopes.

scholarly journals Mass balance of Trambau Glacier, Rolwaling region, Nepal Himalaya: in-situ observations, long-term reconstruction and mass-balance sensitivity

2019 ◽  
Vol 65 (252) ◽  
pp. 605-616 ◽  
Author(s):  
SOJIRO SUNAKO ◽  
KOJI FUJITA ◽  
AKIKO SAKAI ◽  
RIJAN B. KAYASTHA
Keyword(s):  
Mass Balance ◽  
High Elevation ◽  
Climatic Conditions ◽  
Balance Model ◽  
Glacier Mass Balance ◽  
Balance Study ◽  
Nepal Himalaya ◽  
In Situ Data

ABSTRACTWe conducted a mass-balance study of debris-free Trambau Glacier in the Rolwaling region, Nepal Himalaya, which is accessible to 6000 m a.s.l., to better understand mass-balance processes and the effect of precipitation on these processes on high-elevation Himalayan glaciers. Continuous in situ meteorological and mass-balance observations that spanned the three melt seasons from May 2016 are reported. An energy- and mass-balance model is also applied to evaluate its performance and sensitivity to various climatic conditions. Glacier-wide mass balances ranging from −0.34 ± 0.38 m w.e. in 2016 to −0.82 ± 0.53 m w.e. in 2017/18 are obtained by combining the observations with model results for the areas above the highest stake. The estimated long-term glacier mass balance, which is reconstructed using the ERA-Interim data calibrated with in situ data, is −0.65 ± 0.39 m w.e. a−1for the 1980–2018 period. A significant correlation with annual precipitation (r= 0.77,p< 0.001) is observed, whereas there is no discernible correlation with summer mean air temperature. The results indicate the continuous mass loss of Trambau Glacier over the last four decades, which contrasts with the neighbouring Mera Glacier in balance.

Microfluidic passive samplers for in situ collection of live aquatic protists

2014 ◽  
Vol 6 (20) ◽  
pp. 8350-8357 ◽  
Author(s):  
Grant M. Bouchillon ◽  
Jessica Furrer Chau ◽  
George B. McManus ◽  
Leslie M. Shor
Keyword(s):  
High Resolution ◽  
Passive Samplers ◽  
Aquatic Habitats ◽  
Long Term Observation ◽  
In Situ Collection

Examples of microfluidic passive samplers for collecting live protists from aquatic habitats. The samplers allow high-resolution, long-term observation of unstained protists by concentrating and isolating them in nanoliter-scale galleries.

scholarly journals A case of ALM in situ under long-term observation.

Skin Cancer ◽  
2002 ◽  
Vol 17 (2) ◽  
pp. 141-143
Author(s):  
Katsunori MORI ◽  
Takako SHISHIBA
Keyword(s):  
Long Term Observation

scholarly journals Modelling mass balance using photogrammetric and geophysical data: a pilot study at Griesgletscher, Swiss Alps

1999 ◽  
Vol 45 (151) ◽  
pp. 575-583 ◽  
Author(s):  
Andreas Kääb ◽  
Martin Funk
Keyword(s):  
Pilot Study ◽  
Mass Balance ◽  
Surface Strain ◽  
Swiss Alps ◽  
Surface Velocity ◽  
Glacier Mass Balance ◽  
Glacier Surface ◽  
Ice Flow ◽  
Applied Model ◽  
Ice Velocity

AbstractThe kinematic boundary condition al the glacier surface can be used to give glacier mass balance at a point as a function of changes in the surface elevation, and of the horizontal and vertical velocities. Vertical velocity can in turn be estimated from basal slope, basal ice velocity and surface strain. In a pilot study on the tongue of Griesgletscher, Swiss Alps, the applicability of the relation for modelling area-wide ice flow and mass-balance distribution is tested. The key input of the calculations, i.e. the area-wide surface velocity field, is obtained using a newly developed photogrammetric technique. Ice thickness is derived from radar-echo soundings. Error estimates and comparisons with stake measurements show an average accuracy of approximately ±0.3 ma-1for the calculated vertical ice velocity at the surface and ±0.7 ma-1for the calculated mass balance. Due to photogrammetric restrictions and model-inherent sensitivities the applied model appeared to be most suitable for determining area-wide mass balance and ice flow on flat-lying ablation areas, but is so far not very well suited for steep ablation areas and most parts of accumulation areas. Nevertheless, the study on Griesgletscher opens a new and promising perspective for the monitoring of spatial and temporal glacier mass-balance variations.

Modeling of the Russell glacier's basal conditions at seasonal time scale using the satellite observations of surface ice speed

2021 ◽  
Author(s):  
Anna Derkacheva ◽  
Fabien Gillet-Chaulet ◽  
Jeremie Mouginot
Keyword(s):  
Time Series ◽  
Temporal Resolution ◽  
Flow Model ◽  
In Situ Measurements ◽  
Satellite Observations ◽  
Surface Velocity ◽  
Ice Flow ◽  
Surface Ice ◽  
The Impact

&lt;p&gt;Greenland&amp;#8217;s future response to climate change will be determined partly by various phenomena controlling ice flow. For the land-terminating sectors, the water lubricating the glacier's base is considered as a major control on the ice motion. For instance, the seasonal modulations of water input induced by summer melt can cause glacier speed-up up to +200-300% compared to the winter mean. Thus, a comprehensive understanding of variations in the basal conditions, which are at the origin of the glacier flow fluctuations, plays a key role for the climate projections.&lt;/p&gt;&lt;p&gt;While the in-situ measurements stay a local and hard approach to investigate the basal conditions, ice flow modeling offers the possibility to invert for them over the large area based on observations of surface glacier speed and topography. During the last decade, the number of available satellite observations has increased significantly, allowing for far more frequent measurements of the glacier speed and precise reconstruction of the seasonal fluctuations. Here, we investigate the possibility of applying this satellite-derived time-series of surface ice velocity to reconstruct the annual behavior of the basal conditions with 2 weeks temporal resolution using an ice flow model.&lt;/p&gt;&lt;p&gt;The area of this study is Russell glacier located on the southwest coast of Greenland. A time series of surface velocity dataset was created by merging measurements from Sentinel-1&amp;2 and Landsat-8, covering an area up to 100 km inland with 150 m/pix spatial resolution and 2-weeks temporal resolution (Derkacheva et al. 2020). The 3D Full-Stokes ice flow model Elmer/Ice is used to invert for the effective basal friction coefficient for each time step.&amp;#160; Usage of a friction law that has been derived for hard beds (Gagliardini et al., 2007) allows to constrain the variation of the basal effective pressure. Overall, the results from the model inversions give access to the evolution of the basal ice speed, friction, effective and water pressure, floatation fraction throughout a complete year. The results are compared with in-situ measurements in terms of absolute values and show a good agreement. The impact of the flow model setup, regularization, assumptions for the ice rheology, and the impact of noise in the speed data are also examined and compared with in-situ measurements.&lt;/p&gt;

Mass balance and dynamics of a valley glacier measured by high-resolution LiDAR

Polar Record ◽  
2007 ◽  
Vol 43 (4) ◽  
pp. 311-319 ◽  
Author(s):  
W. G. Rees ◽  
N. S. Arnold
Keyword(s):  
Mass Balance ◽  
High Spatial Resolution ◽  
Surface Velocity ◽  
Lidar Data ◽  
Fine Scale ◽  
Surface Geometry ◽  
Digital Elevation ◽  
Valley Glacier ◽  
Better Than

ABSTRACTThe changing surface geometry of the glacier Midre Lovénbreen on Svalbard was investigated using LiDAR data acquired on 9 August 2003 and again on 5 July 2005. The data were processed to generate Digital Elevation Models (DEMs) of unprecedentedly high spatial resolution (2 m) and accuracy (better than 0.15 m). Comparison of the two DEMs allowed the mass balance of the glacier to be determined as more negative than −0.62 m yr−1 water equivalent, about twice as negative as the value estimated from in situ measurements. Comparison of the DEMs also showed that the area of the glacier decreased by around 0.3%, and the position of its margin retreated by around 14 m, from 2003 to 2005. It was also possible to track the motion of fine-scale features in the surface geometry such as meltwater channels, and hence to determine the glacier's surface velocity, in some areas. Typical average speeds were around 1–2 cm per day.

scholarly journals Long-term observation of in situ seismic velocity and attenuation

2003 ◽  
Vol 108 (B6) ◽  
Author(s):  
Keiko Yamamura ◽  
Osam Sano ◽  
Hisashi Utada ◽  
Yasuko Takei ◽  
Shigeru Nakao ◽  
...  
Keyword(s):  
Seismic Velocity ◽  
Long Term Observation

scholarly journals Observations of seasonal and diurnal glacier velocities at Mount Rainier, Washington, using terrestrial radar interferometry

2015 ◽  
Vol 9 (6) ◽  
pp. 2219-2235 ◽  
Author(s):  
K. E. Allstadt ◽  
D. E. Shean ◽  
A. Campbell ◽  
M. Fahnestock ◽  
S. D. Malone
Keyword(s):  
Radar Interferometry ◽  
Surface Velocity ◽  
Spatial And Temporal Variability ◽  
Diurnal Variability ◽  
Alpine Glacier ◽  
Mount Rainier ◽  
Glacier Dynamics ◽  
Central Regions

Abstract. We present surface velocity maps derived from repeat terrestrial radar interferometry (TRI) measurements and use these time series to examine seasonal and diurnal dynamics of alpine glaciers at Mount Rainier, Washington. We show that the Nisqually and Emmons glaciers have small slope-parallel velocities near the summit (< 0.2 m day−1), high velocities over their upper and central regions (1.0–1.5 m day−1), and stagnant debris-covered regions near the terminus (< 0.05 m day−1). Velocity uncertainties are as low as &amp;pm;0.02–0.08 m day−1. We document a large seasonal velocity decrease of 0.2–0.7 m day−1 (−25 to −50 %) from July to November for most of the Nisqually Glacier, excluding the icefall, suggesting significant seasonal subglacial water storage under most of the glacier. We did not detect diurnal variability above the noise level. Simple 2-D ice flow modeling using TRI velocities suggests that sliding accounts for 91 and 99 % of the July velocity field for the Emmons and Nisqually glaciers with possible ranges of 60–97 and 93–99.5 %, respectively, when considering model uncertainty. We validate our observations against recent in situ velocity measurements and examine the long-term evolution of Nisqually Glacier dynamics through comparisons with historical velocity data. This study shows that repeat TRI measurements with > 10 km range can be used to investigate spatial and temporal variability of alpine glacier dynamics over large areas, including hazardous and inaccessible areas.

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