Coastal altimetry products in the Strait of Gibraltar
Coastal altimetry products in the Strait of Gibraltar
This paper analyzes the availability and accuracy of coastal altimetry sea level products in the Strait of Gibraltar. All possible repeats of two sections of the Envisat and AltiKa ground-tracks were used in the eastern and western portions of the strait. For Envisat, along-track sea level anomalies (SLAs) at 18-Hz posting rate were computed using ranges from two sources, namely, the official Sensor Geophysical Data Records (SGDRs) and the outputs of a coastal waveform retracker, the Adaptive Leading Edge Subwaveform (ALES) retracker; in addition, SLAs at 1 Hz were obtained from the Centre for Topographic studies of the Ocean and Hydrosphere (CTOH). For AltiKa, along-track SLA at 40 Hz was also computed both from SGDR and ALES ranges. The sea state bias correction was recomputed for the ALES-retracked Envisat SLA. The quality of these altimeter products was validated using two tide gauges located on the southern coast of Spain. For Envisat, the availability of data close to the coast depends crucially on the strategy followed for data screening. Most of the rejected data were due to the radar instrument operating in a low-precision nonocean mode. We observed an improvement of about 20% in the accuracy of the Envisat SLAs from ALES compared to the standard (SGDR) and the reprocessed CTOH data sets. AltiKa shows higher accuracy, with no significant differences between SGDR and ALES. The use of products from both missions allows longer times series, leading to a better understanding of the hydrodynamic processes in the study area.
Tides, Sea measurements, Sea level, Altimetry, Satellites, Time series analysis
5455-5466
Gomez-Enri, Jesus
1f086a9f-927e-4a9d-b352-f43a2311930f
Cipollini, Paolo
276e356a-f29e-4192-98b3-9340b491dab8
Passaro, Marcello
690f6557-87d1-416b-bf6d-d6819d64932e
Vignudelli, Stefano
2f848cc5-1811-4b8d-9f27-fc933d12a2b4
Tejedor, Begona
1f1e915c-1e3f-47a7-9534-ca4da69449f1
Coca, Josep
1c0b35b3-ea63-42f0-b920-d09eea5b4125
September 2016
Gomez-Enri, Jesus
1f086a9f-927e-4a9d-b352-f43a2311930f
Cipollini, Paolo
276e356a-f29e-4192-98b3-9340b491dab8
Passaro, Marcello
690f6557-87d1-416b-bf6d-d6819d64932e
Vignudelli, Stefano
2f848cc5-1811-4b8d-9f27-fc933d12a2b4
Tejedor, Begona
1f1e915c-1e3f-47a7-9534-ca4da69449f1
Coca, Josep
1c0b35b3-ea63-42f0-b920-d09eea5b4125
Gomez-Enri, Jesus, Cipollini, Paolo, Passaro, Marcello, Vignudelli, Stefano, Tejedor, Begona and Coca, Josep
(2016)
Coastal altimetry products in the Strait of Gibraltar.
IEEE Transactions on Geoscience and Remote Sensing, 54 (9), .
(doi:10.1109/TGRS.2016.2565472).
Abstract
This paper analyzes the availability and accuracy of coastal altimetry sea level products in the Strait of Gibraltar. All possible repeats of two sections of the Envisat and AltiKa ground-tracks were used in the eastern and western portions of the strait. For Envisat, along-track sea level anomalies (SLAs) at 18-Hz posting rate were computed using ranges from two sources, namely, the official Sensor Geophysical Data Records (SGDRs) and the outputs of a coastal waveform retracker, the Adaptive Leading Edge Subwaveform (ALES) retracker; in addition, SLAs at 1 Hz were obtained from the Centre for Topographic studies of the Ocean and Hydrosphere (CTOH). For AltiKa, along-track SLA at 40 Hz was also computed both from SGDR and ALES ranges. The sea state bias correction was recomputed for the ALES-retracked Envisat SLA. The quality of these altimeter products was validated using two tide gauges located on the southern coast of Spain. For Envisat, the availability of data close to the coast depends crucially on the strategy followed for data screening. Most of the rejected data were due to the radar instrument operating in a low-precision nonocean mode. We observed an improvement of about 20% in the accuracy of the Envisat SLAs from ALES compared to the standard (SGDR) and the reprocessed CTOH data sets. AltiKa shows higher accuracy, with no significant differences between SGDR and ALES. The use of products from both missions allows longer times series, leading to a better understanding of the hydrodynamic processes in the study area.
Text
Coastal Altimetry - Gomez-Enri.pdf
- Accepted Manuscript
More information
e-pub ahead of print date: 27 May 2016
Published date: September 2016
Additional Information:
© 2016 IEEE Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The definitive version is available at http://ieeexplore.ieee.org/xpl/periodicals.jsp
Keywords:
Tides, Sea measurements, Sea level, Altimetry, Satellites, Time series analysis
Organisations:
Physical Oceanography, Marine Physics and Ocean Climate
Identifiers
Local EPrints ID: 401874
URI: http://eprints.soton.ac.uk/id/eprint/401874
ISSN: 0196-2892
PURE UUID: 6092ddd6-8a03-4d9e-8638-49fd17735706
Catalogue record
Date deposited: 20 Oct 2016 15:58
Last modified: 15 Mar 2024 02:57
Export record
Altmetrics
Contributors
Author:
Jesus Gomez-Enri
Author:
Paolo Cipollini
Author:
Marcello Passaro
Author:
Stefano Vignudelli
Author:
Begona Tejedor
Author:
Josep Coca
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics