scholarly journals A decade (2002–2012) of supraglacial lake volume estimates across Russell Glacier, West Greenland

2014 ◽  
Vol 8 (1) ◽  
pp. 107-121 ◽  
Author(s):  
A. A. W. Fitzpatrick ◽  
A. L. Hubbard ◽  
J. E. Box ◽  
D. J. Quincey ◽  
D. van As ◽  
...  
Keyword(s):  
Water Volume ◽  
Strongly Correlated ◽  
West Greenland ◽  
Flow Acceleration ◽  
Lake Volume ◽  
Supraglacial Lakes ◽  
Meltwater Runoff ◽  
Hydrological System ◽  
Storage Buffer ◽  
Volume Estimates

Abstract. Supraglacial lakes represent an ephemeral storage buffer for meltwater runoff and lead to significant, yet short-lived, episodes of ice-flow acceleration by decanting large meltwater and energy fluxes into the ice sheet's hydrological system. Here, a methodology for calculating lake volume is used to quantify storage and drainage across Russell Glacier, West Greenland, between 2002 and 2012. Using 502 MODIS scenes, water volume at ~200 seasonally occurring lakes was derived using a depth–reflectance relationship, which was independently calibrated and field validated against lake bathymetry. The inland expansion of lakes is strongly correlated with air temperature: during the record melt years of 2010 and 2012, lakes formed and drained earlier, attaining their maximum volume 38 and 20 days earlier than the 11 yr mean, as well as occupying a greater area and forming at higher elevations (> 1800 m) than previously. Despite occupying under 2% of the study area, lakes delay the transmission of up to 7–13% of the bulk meltwater discharged. Although the results are subject to an observational bias caused by periods of cloud cover, we estimate that across Russell Glacier, 28% of supraglacial lakes drain rapidly (< 4 days). Clustering of such events in space and time suggests a synoptic trigger mechanism. Further, we find no evidence to support a unifying critical size or depth-dependent drainage threshold.

scholarly journals A decade of supraglacial lake volume estimates across a land-terminating margin of the Greenland Ice Sheet

2013 ◽  
Vol 7 (2) ◽  
pp. 1383-1414 ◽  
Author(s):  
A. A. W. Fitzpatrick ◽  
A. L. Hubbard ◽  
J. E. Box ◽  
D. J. Quincey ◽  
D. van As ◽  
...  
Keyword(s):  
Greenland Ice Sheet ◽  
Water Volume ◽  
Strongly Correlated ◽  
Flow Acceleration ◽  
Lake Volume ◽  
Supraglacial Lakes ◽  
Hydrological System ◽  
Storage Buffer ◽  
Optical Satellite Images ◽  
Volume Estimates

Abstract. Supraglacial lakes represent an ephemeral storage buffer for runoff and lead to significant, yet short-lived, episodes of ice-flow acceleration by decanting large fluxes of meltwater and energy into the ice sheet's hydrological system. Here, a field-validated methodology for calculating lake volume is used to quantify storage and drainage across Russell Glacier catchment, west Greenland, from 2002 onwards. Using 502 optical satellite images, water volume at ~200 seasonally occurring lakes was derived from a depth-reflectance relationship, independently calibrated and field-validated against lake bathymetry. Inland expansion of lakes is strongly correlated with air temperature: during the record melt years of 2010 and 2012, lakes formed and drained earlier, attaining their maximum volume 38 and 20 days before the 11 yr mean, as well as occupying a greater area and forming at higher elevations (>1800 m) than previously. Although lakes occupy only 2% of the catchment surface area, they temporarily store up to 13% of the bulk meltwater discharged. Across Russell Glacier, 28% of supraglacial lakes drain rapidly and clustering of such events in space and time suggests a synoptic trigger-mechanism. Furthermore, we find no evidence to support a unifying critical size or depth-dependent drainage threshold hypothesis.

scholarly journals An attempt at a typology of karst lakes in the Połaniec Basin (Małopolska Upland)

2018 ◽  
Vol 15 (1) ◽  
pp. 63-74
Author(s):  
Michał Stachura ◽  
Dariusz Wieczorek ◽  
Artur Zieliński
Keyword(s):  
Cluster Analysis ◽  
Maximum Depth ◽  
The Other ◽  
Water Volume ◽  
Dependence Analysis ◽  
Strongly Correlated ◽  
Lake Volume ◽  
Karst Lakes ◽  
Morphometric Features ◽  
Basin Area

Abstract The main goal of the paper is to attempt a typology of karst lakes in the Połaniec Basin (Małopolska Upland). The typology was conducted on the basis of a dependence analysis of several essential morphometric parameters of lake basins. The considered data comprised 23 lakes with respect to 15 morphometric features. The correlation analysis, mainly of a group of lakes located in single karst sinkholes, revealed that the length and width of basins are strongly correlated. It is also noticeable that basin shape determines lake volume, even though pools of similar water volume may differ in area. Moreover, an increase in the maximum depth of basins does not necessarily imply any increase in volume. Likewise, there is no prevalent dependence between basin area and maximum depth. The cluster analysis, among reasonable indications, generally identified a division of the considered lakes into two sets. One of the sets comprises Duży Staw and Dziki Staw, while the other consists of all the other lakes. Less frequent divisions into three indicated Duży Staw, Dziki Staw, and Czwarty Staw as the leading lakes. Divisions into 19–22 clusters were also suggested, but this does not seem to be reliable. As a consequence, the cluster analysis showed that Duży Staw and Dziki Staw stand out the most from the other lakes. This remainder constitutes rather close to each other, but not an ideally uniform group of lakes.

scholarly journals Surges of Harald Moltke Bræ, north-west Greenland: Seasonal modulation and initiation at the terminus

2020 ◽  
Author(s):  
Lukas Müller ◽  
Martin Horwath ◽  
Mirko Scheinert ◽  
Christoph Mayer ◽  
Benjamin Ebermann ◽  
...  
Keyword(s):  
Ice Flow ◽  
Surface Mass ◽  
West Greenland ◽  
North West ◽  
Flow Acceleration ◽  
Ice Surface ◽  
Meltwater Runoff ◽  
Seasonal Flow ◽  
Order Of Magnitude ◽  
Thickness Variations

Abstract. Harald Moltke Bræ, a marine-terminating glacier in north-west Greenland, shows episodic surges. A recent surge from 2013 to 2019 lasted significantly longer (6 years) than previously observed surges (2–4 years) and exhibits a pronounced seasonality with flow velocities varying by one order of magnitude (between about 0.5 and 10 m/day) in the course of a year. During this six-year period, the velocity always peaked in the early melt season and decreased abruptly when meltwater runoff was maximum. Our data suggest that the seasonality has been similar during previous surges, and, to a much lesser extent, during the intermediate quiescent phases. It is peculiar to Harald Moltke Bræ that the seasonal amplitude is amplified episodically to constitute glacier surges. The surge from 2013 to 2019 was preceded by a rapid frontal retreat and a pronounced thinning at the glacier front (30 m within 3 years). We discuss possible causal mechanisms of the seasonally modulated surge behaviour by involving various system inherent factors (e.g. glacier geometry) and external factors (e.g. surface mass balance). The seasonality may be caused by a transition of an inefficient subglacial system to an efficient one, as known for many glaciers in Greenland. The patterns of flow velocity and ice thickness variations indicate that the surges are initiated at the terminus and develop through an up-glacier propagation of ice flow acceleration. Possibly, this is facilitated by a simultaneous up-glacier spreading of surface crevasses and weakening of subglacial till. Once a large part of the ablation zone has accelerated, conditions may favour substantial seasonal flow acceleration through seasonally changing meltwater availability. Thus the seasonal amplitude remains high for two or more years until the fast ice flow has flattened the ice surface and the glacier stabilizes again.

scholarly journals Inland advance of supraglacial lakes in north-west Greenland under recent climatic warming

2017 ◽  
Vol 59 (76pt1) ◽  
pp. 66-82 ◽  
Author(s):  
Laura A. Gledhill ◽  
Andrew G. Williamson
Keyword(s):  
Ice Sheet ◽  
Drainage System ◽  
Greenland Ice Sheet ◽  
Climatic Warming ◽  
Landsat Images ◽  
West Greenland ◽  
North West ◽  
Supraglacial Lakes ◽  
Hydrological System ◽  
Ice Sheet Dynamics

ABSTRACTThe inland advance of supraglacial lakes (SGLs) towards the interior regions of the Greenland ice sheet (GrIS) may have implications for the water volumes reaching the subglacial drainage system, and could consequently affect long-term ice-sheet dynamics. Here, we investigate changes to the areas, volumes and elevation distributions of over 8000 manually delineated SGLs using 44 Landsat images of a 6200 km2 sector of north-west Greenland over three decades (1985–2016). Our results show that SGLs have advanced to higher maximum (+418 m) and mean (+299 m) elevations, and that there has been a near-doubling of total regional SGL areas and volumes over the study period, accelerating after 2000. These changes were primarily caused by an increased SGL area and volume at high (≥1200 m a.s.l.) elevations, where SGL coverage increased by over 2750% during the study period. Many of the observed changes, particularly the post-2000 accelerations, were driven by changes to regional surface-temperature anomalies. This study demonstrates the past and accelerating response of the GrIS's hydrological system due to climatic warming, indicating an urgent need to understand whether the increasingly inland SGLs will be capable of hydrofracture in the future, thus determining their potential implications for ice-sheet dynamics.

scholarly journals Jakobshavns Isbræ, West Greenland: Seasonal Variations in Velocity - or Lack Thereof

1990 ◽  
Vol 36 (122) ◽  
pp. 82-88 ◽  
Author(s):  
Keith Echelmeyer ◽  
William D. Harrison
Keyword(s):  
Drainage Basin ◽  
Surface Velocity ◽  
West Greenland ◽  
Supraglacial Lakes ◽  
Ice Stream ◽  
Significant Seasonal Variation ◽  
Melt Water ◽  
Basal Sliding ◽  
Seasonal Basis ◽  
Made In

AbstractThe lower 80 km of the fast-moving Jakobshavns Isbræ, West Greenland, is subject to significant melting during the summer season. The melt water drains into large supraglacial rivers which pour into moulins or feed into beautiful supraglacial lakes, some of which are observed to drain periodically. Except for a few streams that drain directly off the margins of the ice sheet within the drainage basin of this glacier, the fate of this melt water is unknown. However, a localized upwelling of highly turbid water is often observed during the melt season in the fjord adjacent Io the terminal cliff of the glacier, indicating that water from some source does move along the glacier bed.As part of an investigation on the mechanisms of rapid flow on Jakobshavns Isbræ, measurements of surface velocity at several (∼25) locations along the ice stream at and below the equilibrium line were made in order to investigate the effects of this seasonally varying input of melt water on the speed of the glacier.No significant seasonal variation in speed was found at any location. This indicates that, unlike many other sub-polar and temperate glaciers, surface melt-water production does not affect the motion of this glacier on a seasonal basis, and, thus, does not cause a significant temporal variation in basal sliding. This finding has important ramifications on the mechanisms of flow for this ice stream.

scholarly journals Estimating the volume of Alpine glacial lakes

2015 ◽  
Vol 3 (4) ◽  
pp. 559-575 ◽  
Author(s):  
S. J. Cook ◽  
D. J. Quincey
Keyword(s):  
Glacial Lake ◽  
Lake Area ◽  
Empirical Relationships ◽  
Main Trunk ◽  
Data Set ◽  
Global Database ◽  
Lake Volume ◽  
Supraglacial Lakes ◽  
Glacial Lake Outburst Flood ◽  
Downstream Communities

Abstract. Supraglacial, moraine-dammed and ice-dammed lakes represent a potential glacial lake outburst flood (GLOF) threat to downstream communities in many mountain regions. This has motivated the development of empirical relationships to predict lake volume given a measurement of lake surface area obtained from satellite imagery. Such relationships are based on the notion that lake depth, area and volume scale predictably. We critically evaluate the performance of these existing empirical relationships by examining a global database of glacial lake depths, areas and volumes. Results show that lake area and depth are not always well correlated (r2 = 0.38) and that although lake volume and area are well correlated (r2 = 0.91), and indeed are auto-correlated, there are distinct outliers in the data set. These outliers represent situations where it may not be appropriate to apply existing empirical relationships to predict lake volume and include growing supraglacial lakes, glaciers that recede into basins with complex overdeepened morphologies or that have been deepened by intense erosion and lakes formed where glaciers advance across and block a main trunk valley. We use the compiled data set to develop a conceptual model of how the volumes of supraglacial ponds and lakes, moraine-dammed lakes and ice-dammed lakes should be expected to evolve with increasing area. Although a large amount of bathymetric data exist for moraine-dammed and ice-dammed lakes, we suggest that further measurements of growing supraglacial ponds and lakes are needed to better understand their development.

scholarly journals Impact of Lake Morphology and Shallowing on the Rate of Overgrowth in Hard-Water Eutrophic Lakes

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1827 ◽  
Author(s):  
Agnieszka Lawniczak-Malińska ◽  
Mariusz Ptak ◽  
Sofia Celewicz ◽  
Adam Choiński
Keyword(s):  
Hard Water ◽  
Strongly Correlated ◽  
Eutrophic Lakes ◽  
Vegetation Growth ◽  
Lake Volume ◽  
Physico Chemical ◽  
Lake Morphology ◽  
West Part ◽  
The 1960S ◽  
Phytoplankton Blooming

Lake disappearance is one of the results of water eutrophication which leads to lake shallowing and overgrowth, and small and shallow lakes are the most threatened with degradation. We studied the effect of lake shallowing on its overgrowth, taking into account the morphometric parameters of water bodies. The study was performed in 20 lakes located in the central west part of Poland. The degree of lake shallowing was evaluated on the basis of bathymetric maps made in the 1960s and studies carried out presently. Additionally, an analysis of littoral coverage and macrophyte growth forms was investigated. Moreover, the composition, intensity of phytoplankton blooming, and physico-chemical parameters of the lake water were analyzed. Redundancy analysis shows that the lake volume, average depth, shallowing rate, and change in volume were the parameters that most strongly correlated with the share of macrophytes in the lakes. According to the regression analysis, the share of emergent macrophytes was significantly correlated with lake shallowing. No relation was found between phytoplankton blooming and lake shallowing. Conversely, the lakes with the highest rate of shallowing were characterized by the greatest share of vegetation, which suggested that vegetation growth had a significant impact on lake shallowing.

Produced Water Volume Estimates and Management Practices

2011 ◽  
Vol 26 (03) ◽  
pp. 234-239 ◽  
Author(s):  
John Veil ◽  
Corrie Clark
Keyword(s):  
Management Practices ◽  
Produced Water ◽  
Water Volume ◽  
Volume Estimates

scholarly journals Glacier mass loss induced the rapid growth of Linggo Co on the central Tibetan Plateau

2012 ◽  
Vol 58 (207) ◽  
pp. 177-184 ◽  
Author(s):  
Yanbin Lei ◽  
Tandong Yao ◽  
Chaolu Yi ◽  
Weicai Wang ◽  
Yongwei Sheng ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Mass Loss ◽  
Rapid Growth ◽  
Lake Level ◽  
Remote Sensing And Gis ◽  
The Past ◽  
Lake Volume ◽  
Meltwater Runoff ◽  
Field Investigations ◽  
Central Tibetan Plateau

AbstractRemote-sensing and GIS techniques in conjunction with field investigations show how glacier mass loss has led to the rapid growth of Linggo Co, a glacier-fed lake on the central Tibetan Plateau, which has expanded by 21.3% in area between 1974 and 2010, with a lake-level rise of ˜11.2m. The lake volume of Linggo Co increased at a rate of 0.02 × 106, 42.67 × 106 and 65.8 × I06m3a-1 during the periods 1974-92, 1992-99 and 1999-2010, respectively. Other nonglacier-fed lakes in the vicinity (i.e. Longwei Co, Amur Co and Darngo Co Ngion) shrank considerably from the early 1970s to 1992 and then expanded from 1992 to 2010. Despite being in the same climate region, Linggo Co and the non-glacier-fed lakes have differed in response to climate change. The glaciers in the catchment of Linggo Co retreated by 2.4% in area between 1974 and 2007, and their mean thickness decreased by 6.19 ± 1.91 m between 1974 and 2000, with an associated glacier meltwater runoff of (7.52 ± 2.32) × 108 m3. The results indicate that glacier mass loss had a significant impact on the growth of Linggo Co over the past 40 years.

scholarly journals Improved processing and calibration of the interferometric mode of the CryoSat radar altimeter allows height measurements of supraglacial lakes in west Greenland

2016 ◽  
Author(s):  
Laurence Gray ◽  
David Burgess ◽  
Luke Copland ◽  
Thorben Dunse ◽  
Kirsty Langley ◽  
...  
Keyword(s):  
Normal Incidence ◽  
Ablation Zone ◽  
Radar Altimeter ◽  
Waveform Data ◽  
West Greenland ◽  
Ice Cap ◽  
Supraglacial Lakes ◽  
Ideal Situation ◽  
Digital Elevation ◽  
Devon Ice Cap

Abstract. We compare geocoded heights derived from the interferometric mode (SARIn) of CryoSat to surface heights from calibration-validation sites on Devon Ice Cap and West Greenland. Comparisons are included for both the heights derived from the first return (the "point-of-closest-approach" or POCA) as well as heights derived from delayed waveform returns ("swath" processing). While swath processed heights are normally less accurate than edited POCA heights, of order 1–5 m instead of order 1–2 m, the increased coverage possible with swath data complements the POCA data and provides useful information for both system calibration and improving digital elevation models (DEMs). We show that the pre-launch interferometric baseline coupled with an additional roll correction (~ 0.0075°), or equivalent phase correction (~ 0.0435 radians), provides an improved calibration of the interferometric SARIn mode. We extend the potential use of SARIn data by showing the influence of surface conditions, especially melt, on the return waveforms, and that it is possible to detect and measure the height of summer supraglacial lakes in West Greenland. A supraglacial lake can provide a strong radar target in the waveform, stronger than the initial POCA return, if viewed at near normal incidence. This provides an ideal situation for swath processing and we demonstrate height accuracies of ~ 0.5 m for two lake sites, one in the accumulation zone and one in the ablation zone, which were measured every year from 2010 or 2011 to 2016. Each year the lake in the ablation zone was viewed in June by ascending passes and then 5.5 days later by descending passes which allows an approximate estimate of the filling rate. The results suggest that CryoSat waveform data and measurements of supraglacial lake height change could complement the use of optical satellite and be helpful as proxy indicators for surface melt around Greenland.

Sign in / Sign up

Export Citation Format

Share Document