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| Titel |
Accuracy improvement of the ice flow rate measurements on Antarctic ice sheet by DInSAR method |
| VerfasserIn |
Kaoru Shiramizu, Koichiro Doi, Yuichi Aoyama |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250108492
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| Publikation (Nr.) |
 EGU/EGU2015-8247.pdf |
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| Zusammenfassung |
| DInSAR (Differential Interferometric Synthetic Aperture Radar) is an effective tool to
measure the flow rate of slow flowing ice streams on Antarctic ice sheet with high resolution.
In the flow rate measurement by DInSAR method, we use Digital Elevation Model (DEM)
at two times in the estimating process. At first, we use it to remove topographic
fringes from InSAR images. And then, it is used to project obtained displacements
along Line-Of-Sight (LOS) direction to the actual flow direction. ASTER-GDEM
widely-used for InSAR prosessing of the data of polar region has a lot of errors
especially in the inland ice sheet area. Thus the errors yield irregular flow rates and
directions. Therefore, quality of DEM has a substantial influence on the ice flow rate
measurement.
In this study, we created a new DEM (resolution 10m; hereinafter referred to as
PRISM-DEM) based on ALOS/PRISM images, and compared PRISM-DEM and
ASTER-GDEM. The study area is around Skallen, 90km south from Syowa Station, in the
southern part of Sôya Coast, East Antarctica.
For making DInSAR images, we used ALOS/PALSAR data of 13 pairs (Path633, Row
571-572), observed during the period from November 23, 2007 through January 16, 2011.
PRISM-DEM covering the PALSAR scene was created from nadir and backward view
images of ALOS/PRISM (Observation date: 2009/1/18) by applying stereo processing with a
digital mapping equipment, and then the automatically created a primary DEM was corrected
manually to make a final DEM.
The number of irregular values of actual ice flow rate was reduced by applying
PRISM-DEM compared with that by applying ASTER-GDEM. Additionally, an averaged
displacement of approximately 0.5cm was obtained by applying PRISM-DEM over outcrop
area, where no crustal displacement considered to occur during the recurrence period of
ALOS/PALSAR (46days), while an averaged displacement of approximately 1.65 cm was
observed by applying ASTER-GDEM. Since displacements over outcrop area are considered
to be apparent ones, the average could be a measure of flow rate estimation accuracy by
DInSAR. Therefore, it is concluded that the accuracy of the ice flow rate measurement can be
improved by using PRISM-DEM.
In this presentation, we will show the results of the estimated flow rate of ice streams in
the region of interest, and discuss the additional accuracy improvement of this method. |
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