| Title | Dual-frequency altimeter signal from Envisat on the Amery Ice Shelf |
| Author | Lacroix, P.; Legrésy, B.; Coleman, R.; Dechambre, M.; Rémy, F. |
| Author Affil | Lacroix, P., UPS, LEGOS, Toulouse, France. Other: University of Tasmania, Australia; CETP, France |
| Source | Remote Sensing of Environment, 109(3), p.285-294. Publisher: Elsevier, New York, NY, United States. ISSN: 0034- 4257 |
| Publication Date | Aug. 15, 2007 |
| Notes | In English. 20 refs. GeoRef Acc. No: 310018. CRREL Acc. No: 65006834 |
| Index Terms | precipitation (meteorology); glacial geology; ice shelves; analysis (mathematics); measurement; remote sensing; snow; Antarctica- -Amery Ice Shelf; Antarctica--East Antarctica; altimetry; Amery Ice Shelf; Antarctica; atmospheric precipitation; East Antarctica; elevation; fissures; glacial features; mathematical methods; roughness; satellite methods; seasonal variations; waveforms |
| Abstract | In Antarctica, radar altimeter measurements are sensitive to dielectric and penetration properties of the sensed medium (snow) such that the spacecraft's altitude can be biased. Since 2002, relatively low frequency radar measurements over the Amery Ice Shelf, east Antarctica, have been acquired using the Envisat dual frequency altimeter at S (3.2 GHz) and Ku (13.6 GHz) bands, which penetrate a few meters into the firn. The altimeter signal is however modified in summer by the presence of snowfilled crevasses. Indeed, the specularity of the snow surfaces in summer makes the altimetric signal sensitive mostly to nadir echoes, that increases the ratio between the crevasse signal and the surrounding ice-shelf signal at nadir. Crevasses are distinguished by differences in backscattering behavior compared with the surrounding ice-shelf signal. Crevasses are characterized by a strong backscatter coefficient at Ku band and anomalies in the S band altitude estimation. These two characteristics make snowfilled crevasses detectable by the dual frequency altimeter of Envisat. (mod. journ. abst.) |
| URL | http://hdl.handle.net/10.1016/j.rse.2007.01.007 |
| Publication Type | journal article |
| Record ID | 91476 |