Synthetic aperture radar detection of the snowline on Commonwealth and Howard Glaciers, Taylor Valley, Antarctica

Bardel, Patrick; Fountain, Andrew G.; Hall, Dorothy K.; Kwok, R.

doi:10.3189/172756402781818021

Cited by 9 publications

(3 citation statements)

References 24 publications

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“…Over this line accumulation dominates, while net glacier ablation occurs below this line (Zemp et al 2007). ELA corresponds to the firn line or the snow line at the end of the melting season on terrestrial apline glaciers (de Wildt 2002); on polar glaciers, where melting does not occur, the snow line is the ELA (Bardel et al 2002).…”

Section: Formationmentioning

confidence: 99%

Glacier

Korteniemi¹,

Nagy²

2014

Encyclopedia of Planetary Landforms

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Section: Formationmentioning

confidence: 99%

Glacier

Korteniemi¹,

Nagy²

2014

Encyclopedia of Planetary Landforms

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“…Microwave radiation is sensitive to surface and subsurface physical properties of snow and ice and is not affected by the usual environmental factors that prevent facies mapping with optical sensors. A number of studies on Greenland [ Bindschadler and Vornberger , 1992; Fahnestock et al , 1993; Jezek et al , 1993, 1994; Long and Drinkwater , 1994, 1999; Wismann and Boehnke 1996] and Antarctica [ Braun et al , 2000; Bardel et al , 2002] have connected snow and ice facies to specific radar signatures derived from both synthetic aperture radar (SAR) and scatterometer data. SAR has also been used with some success in mapping superimposed and glacier ice facies on Svalbard [ Engeset et al , 2002; Konig et al , 2002].…”

Section: Background: Snow and Ice Surface Facies And Previous Workmentioning

confidence: 99%

Snow and ice facies variability and ice layer formation on Canadian Arctic ice caps, 1999–2005

2009

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Time series of enhanced resolution data from the SeaWinds scatterometer aboard QuikScat were used to map the distribution of snow and ice surface facies and ice layer formation in the percolation zone on ice caps in the Queen Elizabeth Islands during the period 1999–2005. Iterative Self‐Organizing Data Analysis classification of the mean postfreeze‐up biweekly average σ0 signal for the 7‐year period resulted in the delineation of four snow and ice surface facies (interpreted as the percolation, saturation, superimposed ice, and glacier ice zones). Analysis with National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis reveals that changes in geopotential height in the troposphere (700, 500, and 300 hPa) and air temperature (700 hPa level) are positively (negatively) correlated with area changes in the glacier ice (percolation and saturation) zones and changes in facies boundary elevation. The change in biweekly‐averaged backscatter following the freeze‐up periods between successive autumns was used to map changes in the distribution of ice layers formed by meltwater percolation and refreezing in the snowpack within the percolation zone. Strongly positive air temperature anomalies at the 700 hPa level in 2001 and 2005 are consistent with extensive ice layer formation in the percolation zones of all ice caps. Such large interannual changes in ice layer formation are likely associated with large changes to the density profile of the snowpack and may be associated with surface elevation changes that are unrelated to changes in surface mass balance.

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“…Winter Synthetic Aperture Radar (SAR) satellite imagery can be used to map different facies based on the intensity of backscatter (σ 0 ; sigma nought) of the SAR signal caused by the elementary scatterers on the glacier surface and near-surface ( Fig. 2; Bardel et al, 2002;Engeset et al, 2002;Wolken et al, 2009). As discussed in more detail in the Results (Section 5.1), the glacier ice and superimposed ice zones typically have the lowest σ 0 of all facies due to the lack of reflectors at depth, the saturation and percolation zones have high σ 0 due to extensive ice layers and pipes within the firn, while the dry snow zone has low σ 0 due to the lack of internal reflectors (Partington, 1998;Langley et al, 2008).…”

mentioning

confidence: 99%

Changes in glacier facies zonation on Devon Ice Cap, Nunavut, detected from SAR imagery and field observations

Jong

Copland

Burgess

2018

Preprint

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Abstract. Envisat ASAR WS images, verified against mass balance, ice core, ground-penetrating radar and air temperature measurements, are used to map changes in the distribution of glacier facies zones across Devon Ice Cap between 2004 and 2011. Glacier ice, saturation/percolation and pseudo dry snow zones are readily distinguishable in the satellite imagery, and the superimposed ice zone can be mapped after comparison with ground measurements. Over the study period there has been a clear upglacier migration of glacier facies, resulting in regions close to the firn line switching from being part of the accumulation area with high backscatter to being part of the ablation area with relatively low backscatter. This has coincided with a rapid increase in positive degree days near the ice cap summit, and an increase in the glacier ice zone from 71 % of the ice cap in 2005 to 92 % of the ice cap in 2011. This has significant implications for the area of the ice cap subject to meltwater runoff.

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Synthetic aperture radar detection of the snowline on Commonwealth and Howard Glaciers, Taylor Valley, Antarctica

Cited by 9 publications

References 24 publications

Glacier

Glacier

Snow and ice facies variability and ice layer formation on Canadian Arctic ice caps, 1999–2005

Changes in glacier facies zonation on Devon Ice Cap, Nunavut, detected from SAR imagery and field observations

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