 |
| Titel |
Radar diagnosis of the subglacial conditions in Dronning Maud Land, East Antarctica |
| VerfasserIn |
S. Fujita, P. Holmlund, K. Matsuoka, H. Enomoto, K. Fukui, F. Nakazawa, S. Sugiyama, S. Surdyk |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1994-0416
|
| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 6, no. 5 ; Nr. 6, no. 5 (2012-10-24), S.1203-1219 |
| Datensatznummer |
250003797
|
| Publikation (Nr.) |
 copernicus.org/tc-6-1203-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| In order to better understand the spatial distribution of subglacial
environments, ground-based radar profiling data were analyzed for a total
distance of ~ 3300 km across Dronning Maud Land, East Antarctica. The
relationship between geometrically corrected bed returned power
[Pcbed]dB in decibels and ice thickness
H was examined. When H is smaller than a~critical value that varies
according to location, [Pcbed]dB tends to
decrease relatively smoothly with increasing H, which is explicable
primarily by the cumulative effect of dielectric attenuation within the ice.
However, at locations where H is larger than the critical H values,
anomalous increases and fluctuations in
[Pcbed]dB were observed, regardless of
the choice of radar frequency or radar-pulse width. In addition, the
amplitude of the fluctuations often range 10 ~ 20 dB. We argue that
the anomalous increases are caused by higher bed reflectivity associated with
the existence of subglacial water. We used these features to delineate frozen
and temperate beds. Approximately two-thirds of the investigated area was
found to have a temperate bed. The beds of the inland part of the ice sheet
tend to be temperate, with the exception of subglacial high mountains. In
contrast, the beds of coastal areas tend to be frozen, with the exception of
fast-flowing ice on the subglacial lowland or troughs. We argue that this new
analytical method can be applied to other regions. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|