Acquisition of Ice Thickness and Ice Surface Characteristics in the Seasonal Ice Zone by CULPIS-X during the US Coast Guard's Arctic Domain Awareness Program

According to the analysis of grey scale range on MSS-4, -5, -6 and -7 channel image films for five snow-ice categories on glacier surface, the grey scale among snow, bare ice, ice pinnacle, moraine-covered ice surface and gully bed has been spread nonlinearly by using duplicative processing on high-contrast film. As a result of the rescaling of grey levels, the colour differences of morphological features of Rongbu Glacier in the Qpmolangma region have been increased on false colour composite photography. It is also shown that using MSS-6 to composite false colour images compared to MSS-5 will supply more information for the interpretation of the glacier area.

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High-resolution ice thickness and bed topography of a land-terminating section of the Greenland Ice Sheet

Earth System Science Data Discussions ◽

10.5194/essdd-7-129-2014 ◽

2014 ◽

Vol 7 (1) ◽

pp. 129-148 ◽

Cited By ~ 4

Author(s):

K. Lindbäck ◽

R. Pettersson ◽

S. H. Doyle ◽

C. Helanow ◽

P. Jansson ◽

...

Keyword(s):

Mass Balance ◽

Sea Level ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Airborne Radar ◽

Ice Thickness ◽

Equilibrium Line Altitude ◽

Bed Topography ◽

Ice Surface ◽

Ice Sheet Dynamics

Abstract. We present ice thickness and bed topography maps with high spatial resolution (250 to 500 m) of a and-terminating section of the Greenland Ice Sheet derived from combined ground-based and airborne radar surveys. The data have a total area of ~12000 km2 and cover the whole ablation area of the outlet glaciers of Isunnguata Sermia, Russell, Leverett, Ørkendalen and Isorlersuup up to the long-term mass balance equilibrium line altitude at ~1600 m above sea level. The bed topography shows highly variable subglacial trough systems, and the trough of the Isunnguata Sermia Glacier is over-deepened and reaches an elevation of several hundreds of meters below sea level. The ice surface is smooth and only reflects the bedrock topography in a subtle way, resulting in a highly variable ice thickness. The southern part of our study area consists of higher bed elevations compared to the northern part. The covered area is one of the most studied regions of the Greenland Ice Sheet with studies of mass balance, dynamics, and supraglacial lakes, and our combined dataset can be valuable for detailed studies of ice sheet dynamics and hydrology. The compiled datasets of ground-based and airborne radar surveys are accessible for reviewers (password protected) at doi.pangaea.de/10.1594/pangaea.830314 and will be freely available in the final revised paper.

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Seasonal changes of ice surface characteristics and productivity in the ablation zone of the Greenland Ice Sheet

The Cryosphere ◽

10.5194/tc-9-487-2015 ◽

2015 ◽

Vol 9 (2) ◽

pp. 487-504 ◽

Cited By ~ 27

Author(s):

D. M. Chandler ◽

J. D. Alcock ◽

J. L. Wadham ◽

S. L. Mackie ◽

J. Telling

Keyword(s):

Remote Sensing ◽

Surface Albedo ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Surface Characteristics ◽

Biological Processes ◽

Ablation Zone ◽

Ice Surface ◽

Surface Productivity ◽

Cryoconite Hole

Abstract. Field and remote sensing observations in the ablation zone of the Greenland Ice Sheet have revealed a diverse range of ice surface characteristics, primarily reflecting the variable distribution of fine debris (cryoconite). This debris reduces the surface albedo and is therefore an important control on melt rates and ice sheet mass balance. Meanwhile, studies of ice sheet surface biological processes have found active microbial communities associated with the cryoconite debris, which may themselves modify the cryoconite distribution. Due to the considerable difficulties involved with collecting ground-based observations of the ice surface, our knowledge of the physical and biological surface processes, and their links, remains very limited. Here we present data collected at a field camp established in the ice sheet ablation zone at 67° N, occupied for almost the entire melt season (26 May–10 August 2012), with the aim of gaining a much more detailed understanding of the physical and biological processes occurring on the ice surface. These data sets include quadrat surveys of surface type, measurements of ice surface ablation, and in situ biological oxygen demand incubations to quantify microbial activity. In addition, albedo at the site was retrieved from AVHRR (Advanced Very High Resolution Radiometer) remote sensing data. Observations of the areal coverage of different surface types revealed a rapid change from complete snow cover to the "summer" (summer study period) ice surface of patchy debris ("dirty ice") and cryoconite holes. There was significant correlation between surface albedo, cryoconite hole coverage and surface productivity during the melt season, but microbial activity in "dirty ice" was not correlated with albedo and varied widely throughout the season. While this link suggests the potential for a remote-sensing approach to monitoring cryoconite hole biological processes, very wide seasonal and spatial variability in net surface productivity demonstrates the need for caution when extrapolating point measurements of biological processes to larger temporal or spatial scales.

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New ice thickness maps of Filchner–Ronne Ice Shelf, Antarctica, with specific focus on grounding lines and marine ice

Antarctic Science ◽

10.1017/s0954102007000661 ◽

2007 ◽

Vol 19 (4) ◽

pp. 521-532 ◽

Cited By ~ 40

Author(s):

A. Lambrecht ◽

H. Sandhäger ◽

D.G. Vaughan ◽

C. Mayer

Keyword(s):

Surface Elevation ◽

Small Scale ◽

Ice Thickness ◽

Line Position ◽

Ice Shelf ◽

Ice Surface ◽

Seismic Sounding ◽

Grounding Line ◽

Data Coverage

AbstractFor the Filchner–Ronne Ice Shelf we have compiled measurements of meteoric ice thickness from many institutions, and several different techniques (e.g. radar and seismic sounding) to produce an improved digital map of meteoric ice thickness. This map has high-resolution compared to previous compilations and serves to highlight small-scale geographic features (e.g. ice plains, grounding-line regions). We have also produced a map of the thickness of marine ice bodies beneath the ice shelf by using borehole density data to calibrate an ice thickness to surface-elevation relation, and then comparing maps of ice surface elevation and meteoric ice thickness to infer marine ice thickness. Due to denser data coverage and the improved density-depth relation, the resulting map is a significant improvement on its predecessors and allows insight into the glaciological context of the ice shelf, in particular, into the location of the grounding lines on the southern Ronne Ice Shelf. Here the data were supplemented with barometric determination of surface elevation, which were used to locate the grounding line position. The final delineation of the grounding line position was confirmed by reference to satellite imagery, and revealed that earlier estimates were substantially in error, especially in the area of Foundation Ice Stream and Möllereisstrom.

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Airborne radar survey above Vostok region, east-central Antarctica: ice thickness and Lake Vostok geometry

Journal of Glaciology ◽

10.3189/172756502781831656 ◽

2002 ◽

Vol 48 (160) ◽

pp. 62-69 ◽

Cited By ~ 32

Author(s):

Ignazio E. Tabacco ◽

Cesido Bianchi ◽

Achille Zirizzotti ◽

Enrico Zuccheretti ◽

Alessandro Forieri ◽

...

Keyword(s):

Major Axis ◽

Radar Data ◽

Surface Elevation ◽

Airborne Radar ◽

Ice Thickness ◽

Maximum Width ◽

East Central ◽

Absolute Value ◽

Lake Vostok ◽

Ice Surface

AbstractDuring the 1999–2000 Italian Expedition, an airborne radar survey was performed along 12 transects across Lake Vostok, Antarctica, and its western and eastern margins. Ice thickness, subglacial elevation and the precise location of lake boundaries were determined. Radar data confirm the geometry derived from previous surveys, but with some slight differences. We measured a length of up to 260 km, a maximum width of 81 km and an area of roughly 14 000 km2. Along the major axis, from north to south, the ice thickness varies from 3800 to 4250 m, with a decreasing gradient. From west to east the ice thickness is fairly constant, except for two narrow strips located on the western and eastern margins, where it increases with high thickening rate. Over the lake the surface elevation increases from 3476 m a.s.l. (south) to 3525 (north), with a decreasing gradient, while the lake surface elevation decreases from −315 to −750 m a.s.l., with a decreasing gradient (absolute value). The ice-surface and lake-ceiling slopes suggest that the lake is in a state of hydrostatic equilibrium.

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Stagnant Ice at the Bed of White Glacier, Axel Heiberg Island. N.W.T., Canada

Annals of Glaciology ◽

10.1017/s0260305500200724 ◽

1987 ◽

Vol 9 ◽

pp. 35-38 ◽

Cited By ~ 3

Author(s):

Heinz Blatter

Keyword(s):

Temperature Measurements ◽

Geological Survey ◽

Ice Thickness ◽

Glacier Tongue ◽

Accumulation Zone ◽

The Us ◽

Radio Echo Sounding ◽

Axel Heiberg Island ◽

Echo Sounding

A total of 400 soundings along 15 profiles were obtained on White Glacier, Axel Heiberg Island, N.W.T. with a monopulse radar equipment that was rebuilt according to a model of the US Geological Survey. The resulting data allowed maps to be compiled of the ice thickness for the glacier tongue, The radio echo-sounding data and englacial temperature measurements give some indication of the existence of stagnant ice in depressions of the glacier bed in the accumulation zone of White Glacier.

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Long-Term Glacier Variations Measured by Photogrammetry. A Re-Survey of Tunsbergdalsbreen after 24 Years

Journal of Glaciology ◽

10.3189/s002214300001902x ◽

1966 ◽

Vol 6 (43) ◽

pp. 3-18

Author(s):

W. Kick

Keyword(s):

Eastern Alps ◽

Ice Thickness ◽

Surface Level ◽

Ice Surface ◽

Geodetic Measurements ◽

Alpine Glaciers ◽

Transverse Profile

AbstractThe relations between geodetic measurements of the surface level variations Δh and net budget measurements by stakes arc discussed. In 1961, 24 yr. after Finsterwalder’s survey, Tunsbergdalsbreen, the largest and most regular of the 26 outlet glaciers of Jostedalsbreen, was re-surveyed. The variations in the length, area, ice thickness, and volume of its tongue are shown. The lake Brimkjelen was 99 m. deep in 1937; it disappeared in 1949. From 1900–40 the whole Jostedalsbre lost 0.4 m./yr., about the same amount as the glaciers of the eastern Alps. The ice thickness of the Tunsbergdalsbre tongue diminished by −ΔhA = 0.46+0.0022 (1500−A) m./yr. from 1937–61; for the eastern Alps from 1920–50 −ΔhA ≈ 0.53+0.0021 (2850−A) m./yr. where A is the altitude. The change of Δh with altitude is much the same. The amounts of the retreat of the Alpine glaciers, of Tunsbergdalshreen, and at Werenskioldbreen, Vestspitsbergen, were the greater the higher the latitude. The numerical relations between Δh, net budget, and ice movement are shown. The temporary velocity transverse profile of 1937 served as a prototype for the streaming mode of flow, but in 1961 the glacier partially showed Blockschollen movement, although the velocity had decreased by more than 30 per cent. The article is accompanied by a map showing ice surface contours in 1937 and 1961.

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Mass and enthalpy budget evolution during the surge of a polythermal glacier: a test of theory

Journal of Glaciology ◽

10.1017/jog.2019.63 ◽

2019 ◽

Vol 65 (253) ◽

pp. 717-731 ◽

Cited By ~ 5

Author(s):

Douglas I. Benn ◽

Robert L. Jones ◽

Adrian Luckman ◽

Johannes J. Fürst ◽

Ian Hewitt ◽

...

Keyword(s):

Frictional Heating ◽

Drainage System ◽

Frictional Heat ◽

Balance Theory ◽

Ice Thickness ◽

Resolution Time ◽

Geothermal Heat ◽

Ice Surface ◽

Air Temperatures ◽

Polythermal Glacier

AbstractAnalysis of a recent surge of Morsnevbreen, Svalbard, is used to test predictions of the enthalpy balance theory of surging. High-resolution time series of velocities, ice thickness and crevasse distribution allow key elements of the enthalpy (internal energy) budget to be quantified for different stages of the surge cycle. During quiescence (1936–1990), velocities were very low, and geothermal heat slowly built-up enthalpy at the bed. Measurable mass transfer and frictional heating began in 1990–2010, then positive frictional heating-velocity feedbacks caused gradual acceleration from 2010 to 2015. Rapid acceleration occurred in summer 2016, when extensive crevassing and positive air temperatures allowed significant surface to bed drainage. The surge front reached the terminus in October 2016, coincident with a drop in velocities. Ice plumes in the fjord are interpreted as discharge of large volumes of supercooled water from the bed. Surge termination was prolonged, however, indicating persistence of an inefficient drainage system. The observations closely match predictions of the theory, particularly build-up of enthalpy from geothermal and frictional heat, and surface meltwater, and the concomitant changes in ice-surface elevation and velocity. Additional characteristics of the surge reflect spatial processes not represented in the model, but can be explained with respect to enthalpy gradients.

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Sea Ice in the Greenland Polynya in 2018 - A Study with CryoSat-2 and SMOS

10.5194/egusphere-egu2020-5495 ◽

2020 ◽

Author(s):

Weixin Zhu ◽

Lu Zhou ◽

Shiming Xu

Keyword(s):

Sea Ice ◽

Global Climate ◽

Arctic Sea Ice ◽

Climate System ◽

The Arctic ◽

Ice Thickness ◽

Sea Ice Thickness ◽

The North ◽

Ice Surface ◽

Snow Conditions

AbstractArctic sea ice is a critical component in the global climate system. It affects the climate system by radiating incident heat back into space and regulating ocean-atmosphere heat and momentum. Satellite altimetry such as CryoSat-2 serves as the primary approach for observing sea ice thickness. Nevertheless, the thickness retrieval with CryoSat-2 mainly depends on the height of the ice surface above the sea level, which leads to significant uncertainties over thin ice regimes. The sea ice at the north of Greenland is considered one of the oldest and thickest in the Arctic. However, during late February - early March 2018, a polynya formed north to Greenland due to extra strong southern winds. We focus on the retrieval of sea ice thickness and snow conditions with CryoSat-2 and SMOS during the formation of the polynya. Specifically, we investigate the uncertainty of CryoSat-2 and carry out inter- comparison of sea ice thickness retrieval with SMOS and CryoSat-2/SMOS synergy. Besides, further discussion of retrieval with CryoSat-2 is provided for such scenarios where the m&#233;lange of thick ice and newly formed thin ice is present.

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