Evaluation of data sources for glacial meltwater features
2009 (English)Conference paper (Other academic)
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 lineations and other large scale accumulation features. Landforms created by meltwater have often been neglected in these efforts. Meltwater features such as channels, deltas and relict 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, and ice-dammed lake drainage channels) in comparison with the traditional mapping from aerial photographs. Several sets of satellite images (Landsat ETM+, ASTER, SPOT, and IRS) and DEMs (NEXTMap Britain, Panorama, National elevation dataset of Sweden, and DEM of National Land Survey of Finland) were employed to map the landform record of three reference areas, located in NW Scotland, NE Finland and W Sweden. ASTER images performed significantly better than the panchromatic band of Landsat 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 like meltwater channels. Hence, satellite imagery and DEMs of intermediate resolution contain meltwater system information at a general level that allow 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 fulfill the need of a particular mapping effort. Stereo interpretation of aerial photographs continues to be an advisable method for local meltwater system reconstructions; alternatively, it can be replaced by mapping from high-detail DEMs. For regional to sub-continental reconstructions, the use of ASTER satellite imagery is recommended, because it provides both spectral and spatial resolution suitable for the identification of meltwater features on a medium to large scale.
Place, publisher, year, edition, pages
meltwater, deglaciation, paleoglaciology, remote sensing
Research subject Physical Geography
IdentifiersURN: urn:nbn:se:su:diva-33192OAI: oai:DiVA.org:su-33192DiVA: diva2:282597
CANQUA Meeting 2009, Vancouver, Canada