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Titel |
River ice flux and water velocities along a 600 km-long reach of Lena River, Siberia, from satellite stereo |
VerfasserIn |
A. Kääb, M. Lamare, M. Abrams |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 17, no. 11 ; Nr. 17, no. 11 (2013-11-26), S.4671-4683 |
Datensatznummer |
250086005
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Publikation (Nr.) |
copernicus.org/hess-17-4671-2013.pdf |
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Zusammenfassung |
Knowledge of water-surface velocities in rivers is useful for understanding
a range of river processes. In cold regions, river-ice break up and the
related downstream transport of ice debris is often the most important
hydrological event of the year, leading to flood levels that typically
exceed those for the open-water period and to strong consequences for river
infrastructure and ecology. Accurate and complete surface-velocity fields on
rivers have rarely been produced. Here, we track river ice debris over a
time period of about one minute, which is the typical time lag between the
two or more images that form a stereo data set in spaceborne, along-track
optical stereo mapping. Using a series of nine stereo scenes from the
US/Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer
(ASTER) onboard the NASA Terra spacecraft with 15 m image resolution, we
measure the ice and water velocity field over a 620 km-long reach of the
lower Lena River, Siberia, just above its entry into the Lena delta. Careful
analysis and correction of higher-order image and sensor errors enables an
accuracy of ice-debris velocities of up to 0.04 m s−1 from the ASTER
data. Maximum ice or water speeds, respectively, reach up to 2.5 m s−1
at the time of data acquisition, 27 May 2011 (03:30 UTC). Speeds show clear
along-stream undulations with a wavelength of about 21 km that agree well
with variations in channel width and with the location of sand bars along
the river reach studied. The methodology and results of this study could be
valuable to a number of disciplines requiring detailed information about
river flow, such as hydraulics, hydrology, river ecology and natural-hazard
management. |
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