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Evaluation of data sources for mapping glacial meltwater features
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). (Paleoglaciology)
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). (Paleoglaciology)
2012 (Engelska)Ingår i: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 33, nr 8, s. 2355-2377Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The meltwater system of disintegrating ice sheets provides an important source of information for the reconstruction of ice-retreat patterns during deglaciation. Recent method development in glacial geomorphology, using satellite imagery and digital elevation models (DEMs) for glacial landform mapping, has predominantly been focused on the identification of lineation and other large-scale accumulation features. Landforms created by meltwater have often been neglected in these efforts. Meltwater features such as channels, deltas and fossil shorelines were traditionally mapped using stereo interpretation of aerial photographs. However, during the transition into the digital era, driven by a wish to cover large areas more economically, meltwater features were lost in most mapping surveys. We have evaluated different sets of satellite images and DEMs for their suitability to map glacial meltwater features (lateral meltwater channels, eskers, deltas, ice-dammed lake drainage channels and fossil shorelines) in comparison with the traditional mapping from aerial photographs. Several sets of satellite images and DEMs were employed to map the landform record of three reference areas, located in northwestern Scotland, northeastern Finland and western Sweden. The employed satellite imagery consisted of Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Satellite Pour l’Observation de la Terre (SPOT) 5 and Indian Remote Sensing (IRS)1C, and the DEMs used were from NEXTMap Britain, Panorama, National elevation data set of Sweden and National Land Survey of Finland. ASTER images yielded better results than the panchromatic band of Landsat 7 ETM+ in all three regions, despite the same spatial resolution of the data. In agreement with previous studies, this study shows that DEMs display accumulation features such as eskers suitably well. Satellite images are shown to be insufficiently detailed for the interpretation of smaller features such as meltwater channels. Hence, satellite imagery and DEMs of intermediate resolution contain meltwater system information only at a general level that allows for the identification of landforms of medium to large sizes. It is therefore pertinent that data with an appropriate spatial and spectral resolution are accessed to fulfil the need of a particular mapping effort. Stereointerpretation of aerial photographs continues to be an advisable method for local meltwater system reconstructions; alternatively, it can be replaced by mapping fromhigh-resolution DEMs such as NEXTMap Britain. For regional to sub-continental reconstructions, the use of ASTER satellite imagery is recommended, because it provides both spectral and spatial resolutions suitable for the identification of meltwater features on a medium to large scale.

Ort, förlag, år, upplaga, sidor
2012. Vol. 33, nr 8, s. 2355-2377
Nationell ämneskategori
Naturgeografi
Forskningsämne
naturgeografi
Identifikatorer
URN: urn:nbn:se:su:diva-67391DOI: 10.1080/01431161.2011.608738ISI: 000302162700002OAI: oai:DiVA.org:su-67391DiVA, id: diva2:470126
Tillgänglig från: 2011-12-28 Skapad: 2011-12-28 Senast uppdaterad: 2018-01-12Bibliografiskt granskad
Ingår i avhandling
1. Retreat pattern and dynamics of glaciers and ice sheets: reconstructions based on meltwater features
Öppna denna publikation i ny flik eller fönster >>Retreat pattern and dynamics of glaciers and ice sheets: reconstructions based on meltwater features
2012 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Glaciers and ice sheets covered extensive areas in the Northern Hemisphere during the last glacial period. Subsequently to the Last Glacial Maximum (LGM), they retreated rapidly and, except for Greenland and some other ice caps and glaciers, they vanished after the last glacial termination. This thesis examines the dynamics of deglacial environments by analysing the glacial geomorphological record with focus on the landforms created by glacial meltwater. The aims are (i) to evaluate the data available for mapping glacial meltwater features at the regional scale, and (ii) to demonstrate the potential of such features for regional ice retreat reconstructions in high-relief landscapes. Meltwater landforms such as ice-marginal meltwater channels, eskers, deltas and fossil glacial lake shorelines are used to infer former ice surface slope directions and successive positions of retreating ice margins.

Evaluated high-resolution satellite imagery and digital elevation models reveal their potential to replace aerial photographs as the primary data for mapping glacial meltwater landforms. Following a methods study, reconstructions of the deglacial dynamics are carried out for central Transbaikalia, Siberia, Russia, and for the Cordilleran Ice Sheet (CIS) in central British Columbia, Canada, using regional geomorphological mapping surveys.

Mapped glacial landforms in central Transbaikalia show evidence of a significant glaciation that possibly extended beyond the high mountain areas. Large glacial lakes were formed as advancing glaciers blocked rivers, and of these, Glacial Lake Vitim was the most prominent.

Deglacial dynamics of the CIS reveals that the ice divide shifted to the Coast Mountains in north-central British Columbia and the eastern ice margin retreated towards the ice divide in late glacial time.

This thesis demonstrates the potential to reconstruct ice retreat patterns and deglacial dynamics at regional scales by interpretation of the meltwater landform record.

Ort, förlag, år, upplaga, sidor
Stockholm: Department of Physical Geography and Quaternary Geology, Stockholm University, 2012. s. 17
Serie
Dissertations from the Department of Physical Geography and Quaternary Geology, ISSN 1653-7211 ; 30
Nyckelord
Palaeoglaciology, Cordilleran Ice Sheet, deglaciation, glacial meltwater features, glacial lake
Nationell ämneskategori
Naturgeografi
Forskningsämne
naturgeografi
Identifikatorer
urn:nbn:se:su:diva-68958 (URN)978-91-7447-429-9 (ISBN)
Disputation
2012-02-10, De Geersalen, Geovetenskapens hus, Svante Arrhenius väg 14, Stockholm, 13:00 (Engelska)
Opponent
Handledare
Anmärkning
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Submitted. Paper 6: Manuscript. Tillgänglig från: 2012-01-19 Skapad: 2012-01-09 Senast uppdaterad: 2018-01-12Bibliografiskt granskad

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Margold, MartinJansson, Krister
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Institutionen för naturgeografi och kvartärgeologi (INK)
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