Internal Waves at the UK Continental Shelf: Automatic Mapping Using the ENVISAT ASAR Sensor

Kurekin, A; Land, PE; Miller, PI. 2020 Internal Waves at the UK Continental Shelf: Automatic Mapping Using the ENVISAT ASAR Sensor. Remote Sensing, 12 (15). 2476. https://doi.org/10.3390/rs12152476

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Official URL: http://dx.doi.org/10.3390/rs12152476

Abstract/Summary

Oceanic internal waves occur within stratified water along the boundary between water layers of different density and are generated when strong tidal currents flow over seabed topography. Their amplitude can exceed 50 m and they transport energy over long distances and cause vertical mixing when the waves break. This study presents the first fully automated methodology for the mapping of internal waves using satellite synthetic aperture radar (SAR) data and applies this to explore their spatial and temporal distribution within UK shelf seas. The new algorithm includes enhanced edge detection and spatial processing to target the appearance of these features on satellite images. We acquired and processed over 7000 ENVISAT ASAR scenes covering the UK continental shelfbetween2006and2012,toautomaticallygeneratedetailedmapsofinternalwaves. Monthlyand annual internal wave climatology maps of the continental shelf were produced showing spatial and temporal variability, which can be used to predict where internal waves have the most impact on the seabed environment and ecology in UK shelf seas. These observations revealed correlations between thetemporalpatternsofinternalwavesand theseasonswhenthecontinentalshelfwatersweremore stratified. The maps were validated using well-known seabed topographic features. Concentrations of internal waves were automatically identified at Wyville-Thomson Ridge in June 2008, at the continental shelf break to the east of Rosemary Bank in January 2010 and in the Faroe-Shetland Channel in June 2011. This new automated methodology has been shown to be robust for mapping internalwavesusingalargeSARdatasetandisrecommendedforstudiesinotherregionsworldwide and for SAR data acquired by other sensors.

Item Type: Publication - Article
Additional Information. Not used in RCUK Gateway to Research.: Correspondence: anku@pml.ac.uk; Tel.: +44-1752-633-481 Acknowledgments: The authors would like to thank John Hartley as the Director of Hartley Anderson Limited for organising the financial support of this work. We are also thankful to Vasyl Vlasenko from the School of Biological and Marine Sciences, University of Plymouth, for his valuable consulting support.
Additional Keywords: internal waves; frequency maps; synthetic aperture radar; SAR; remote sensing; image processing; edge detection
Subjects: Data and Information
Earth Observation - Remote Sensing
Oceanography
Divisions: Plymouth Marine Laboratory > National Capability categories > NERC Earth Observation Data Acquisition & Analysis Service (NEODAAS)
Plymouth Marine Laboratory > Science Areas > Earth Observation Science and Applications
Depositing User: S Hawkins
Date made live: 12 Aug 2020 08:11
Last Modified: 19 Aug 2020 08:12
URI: http://plymsea.ac.uk/id/eprint/9023

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