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Titel |
Characterization of L-band synthetic aperture radar (SAR) backscatter from floating and grounded thermokarst lake ice in Arctic Alaska |
VerfasserIn |
M. Engram, K. W. Anthony, F. J. Meyer, G. Grosse |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1994-0416
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Digitales Dokument |
URL |
Erschienen |
In: The Cryosphere ; 7, no. 6 ; Nr. 7, no. 6 (2013-11-14), S.1741-1752 |
Datensatznummer |
250085180
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Publikation (Nr.) |
copernicus.org/tc-7-1741-2013.pdf |
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Zusammenfassung |
Radar remote sensing is a well-established method to discriminate lakes
retaining liquid-phase water beneath winter ice cover from those that do
not. L-band (23.6 cm wavelength) airborne radar showed great promise in the
1970s, but spaceborne synthetic aperture radar (SAR) studies have focused
on C-band (5.6 cm) SAR to classify lake ice with no further attention to
L-band SAR for this purpose. Here, we examined calibrated L-band single- and
quadrature-polarized SAR returns from floating and grounded lake ice in two
regions of Alaska: the northern Seward Peninsula (NSP) where methane ebullition
is common in lakes and the Arctic Coastal Plain (ACP) where ebullition is
relatively rare. We found average backscatter intensities of −13 dB and
−16 dB for late winter floating ice on the NSP and ACP, respectively, and −19 dB
for grounded ice in both regions. Polarimetric analysis revealed that the
mechanism of L-band SAR backscatter from floating ice is primarily roughness
at the ice–water interface. L-band SAR showed less contrast between floating
and grounded lake ice than C-band; however, since L-band is sensitive to
ebullition bubbles trapped by lake ice (bubbles increase backscatter), this
study helps elucidate potential confounding factors of grounded ice in
methane studies using SAR. |
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