Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland
Abstract Using an active transponder with the ERS-I and ERS-2 radar altimeters, the distance to the satellite was measured at a location close to the GRIP site, Greenland, at an altitude of 3.2 km. The measurement was executed while the transponder was in the “ice-tracking mode”. It includes a bias...
Published in: | Journal of Glaciology |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
1998
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1017/s0022143000002124 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000002124 |
id |
crcambridgeupr:10.1017/s0022143000002124 |
---|---|
record_format |
openpolar |
spelling |
crcambridgeupr:10.1017/s0022143000002124 2024-05-19T07:41:16+00:00 Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland Haardenog-Pedersen, G. Keller, K. Tscherning, C. C. Gundestrup, N. 1998 http://dx.doi.org/10.1017/s0022143000002124 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000002124 en eng Cambridge University Press (CUP) Journal of Glaciology volume 44, issue 148, page 625-633 ISSN 0022-1430 1727-5652 journal-article 1998 crcambridgeupr https://doi.org/10.1017/s0022143000002124 2024-05-02T06:50:39Z Abstract Using an active transponder with the ERS-I and ERS-2 radar altimeters, the distance to the satellite was measured at a location close to the GRIP site, Greenland, at an altitude of 3.2 km. The measurement was executed while the transponder was in the “ice-tracking mode”. It includes a bias due to the propagation delay. The location of the transponder was determined using the global positioning system. The transponder signal was modeled and the distance from the altimeter to the effective reflection point of the transponder was determined. Since the transponder was located within 1 km of the ground tracks, the measurement was corrected for this offset. A correction was also done for the surface slope, resulting in the distance (plus bias) to the closest sub-satellite point on the surface of the (compact) snow. The transponder signal was then removed from the radar altimeter waveform, enabling the determination of the distance (plus bias from the altimeter to the first reflective surface within the snow. The différence between this distance and that obtained using the transponder was < 2 m. This shows that the surface which gives rise to the first return of the reflection agrees with the surface of the (compact, dry) snow at this high-altitude location. This is an important result to be used when studying ice-cap topography using satellite radar altimetry. Article in Journal/Newspaper Greenland GRIP Ice cap Journal of Glaciology Cambridge University Press Journal of Glaciology 44 148 625 633 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract Using an active transponder with the ERS-I and ERS-2 radar altimeters, the distance to the satellite was measured at a location close to the GRIP site, Greenland, at an altitude of 3.2 km. The measurement was executed while the transponder was in the “ice-tracking mode”. It includes a bias due to the propagation delay. The location of the transponder was determined using the global positioning system. The transponder signal was modeled and the distance from the altimeter to the effective reflection point of the transponder was determined. Since the transponder was located within 1 km of the ground tracks, the measurement was corrected for this offset. A correction was also done for the surface slope, resulting in the distance (plus bias) to the closest sub-satellite point on the surface of the (compact) snow. The transponder signal was then removed from the radar altimeter waveform, enabling the determination of the distance (plus bias from the altimeter to the first reflective surface within the snow. The différence between this distance and that obtained using the transponder was < 2 m. This shows that the surface which gives rise to the first return of the reflection agrees with the surface of the (compact, dry) snow at this high-altitude location. This is an important result to be used when studying ice-cap topography using satellite radar altimetry. |
format |
Article in Journal/Newspaper |
author |
Haardenog-Pedersen, G. Keller, K. Tscherning, C. C. Gundestrup, N. |
spellingShingle |
Haardenog-Pedersen, G. Keller, K. Tscherning, C. C. Gundestrup, N. Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland |
author_facet |
Haardenog-Pedersen, G. Keller, K. Tscherning, C. C. Gundestrup, N. |
author_sort |
Haardenog-Pedersen, G. |
title |
Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland |
title_short |
Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland |
title_full |
Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland |
title_fullStr |
Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland |
title_full_unstemmed |
Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland |
title_sort |
modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the grip camp, greenland |
publisher |
Cambridge University Press (CUP) |
publishDate |
1998 |
url |
http://dx.doi.org/10.1017/s0022143000002124 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000002124 |
genre |
Greenland GRIP Ice cap Journal of Glaciology |
genre_facet |
Greenland GRIP Ice cap Journal of Glaciology |
op_source |
Journal of Glaciology volume 44, issue 148, page 625-633 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000002124 |
container_title |
Journal of Glaciology |
container_volume |
44 |
container_issue |
148 |
container_start_page |
625 |
op_container_end_page |
633 |
_version_ |
1799480861787160576 |