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Australia: The Land Where Time Began |
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Greenland Ice Flow for the international Polar Year 2008-2009
According to Rignot & Mouginot for a variety of glaciological and
geophysical analyses and modelling, a digital representation of the ice
surface velocity is essential. In this Paper Rignot & Mouginot present a
new, reference, comprehensive, high-resolution, digital mosaic of the
motion of ice in Greenland that was assembled from satellite radar
interferometry data that had been acquired by the Envisat Advanced
Synthetic Aperture Radar (ASAR) during the International Polar Year
2008-2009, the Advanced Land Observation System (ALOS)’s Phase-Array
L-band SAR (PALSAR) and the RADASAT-1 SAR that covers an area of 99 % of
the ice sheet. The ALOS PALSAR date produced the best mapping
performance as a result of higher levels of temporal coherence at the
L-band frequency; but C-band frequency SAR data are affected less by the
ionosphere. Various flow regimes are revealed that range from patterned
enhanced flow in a few large glaciers in cold, low-precipitation areas
of north Greenland; to diffuse, enhanced flow into many, narrow glaciers
that are moving rapidly, in the warmer, high-precipitation sectors of
northwest and southeast Greenland, are
revealed by the ice motion map. The 100 fastest glaciers, greater than
800 m/yr, drain an area of 66 % of the ice sheet, marine-terminating
glaciers drain 88 % of Greenland, and the internal deformation over more
than 50 % of the ice sheet is dominated by basal-sliding motion.
Significant new constraints on ice flow modelling are provided by this
view of ice sheet motion.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |