URL: http://www.altimetry.info/html/use_cases/data_use_case_icecap2_en.html
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URL: http://www.altimetry.info/html/use_cases/data_use_case_icecap2_en.html |
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Data use cases
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| Ice caps |
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2.2.2 Ice caps applications:
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In the S-band, the radar waves penetrates deeper in the snow and ice than the Ku-band and it is less sensitive to the slope effect than the Ku-band. From this known physical properties, we're able to see differences on high altitude areas: over Central-East Antarctica, the S-band waves are less
constrained by the slope effect and less attenuated by the snow grain, providing a bigger return echo than the Ku-band. This is clearly visible on the map below for the cycle 040 (Aug.-Sep.2005) where over East Antarctica, a long area with a north-south direction shows a positive difference between the two bands.
On the contrary, the Ku-band gives higher values over East Antarctica margins.
In southern winter (Envisat cycle 034, Jan.-Feb. 2005) and in southern summer (Envisat cycle 040, August-Sept. 2005), the figures below are quite similar (except for the resolution), we find essentially the same distribution for the backscatter difference.
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| Backcatter coefficient difference (in dB) between the S and the Ku-bands over Antarctica, from Envisat cycle 034 (left) and 040 (right). As explained above, we give an example with two different geographical resolutions: 1/3° on the left and 1° on the right. | |
The leading edge width in S-band tends to have smaller values than the Ku-band one toward the coastal areas over Greenland. On the contrary, the leading edge width in S-band has higher values on the plateau and its distribution seems to be lightly larger during winter (Envisat cycle 034 -below, left-).
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| Leading edge with difference (in m) between the S and the Ku-bands over Greenland, from Envisat cycle 034 (left) and 040 (right). | |
Further information: