The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

Source regions of infragravity waves recorded at the bottom of the equatorial Atlantic Ocean, using OBS of the PI‐LAB experiment

Source regions of infragravity waves recorded at the bottom of the equatorial Atlantic Ocean, using OBS of the PI‐LAB experiment
Source regions of infragravity waves recorded at the bottom of the equatorial Atlantic Ocean, using OBS of the PI‐LAB experiment
Infragravity waves are generated along coasts, and some small fraction of their energy escapes to the open oceans and propagates with little attenuation. Due to the scarcity of deep‐ocean observations of these waves, the mechanism and the extent of the infragravity waves energy leakage from the coasts remains poorly understood. Understanding the generation and pathways of infragravity wave energy is important among others for understanding the breakup of ice‐shelves, and the contamination of high‐resolution satellite radar altimetry measurements of sea level. We examine data from 37 differential pressure gauges of Ocean Bottom Seismometers (OBS) near the equatorial mid‐Atlantic ridge, deployed during the Passive Imaging of the Lithosphere‐Asthenosphere Boundary (PI‐LAB) experiment. We use the beamforming technique to investigate the incoming directions of infragravity waves. Next, we develop a graph‐theory‐based global back‐projection method of noise cross‐correlation function envelopes, which minimizes the effects of array geometry using an adaptive weighting scheme. This approach allows us to locate the sources of the infragravity energy. We assess our observations by comparing to a global model of infragravity wave heights. Our results reveal strong coherent energy from sources and/or reflected phases at the west coast of Africa and some sources from South America. These energy sources are in good agreement with the global infragravity wave model. In addition, we also observe infragravity waves arriving from North America during specific events that mostly occur during Oct‐Feb 2016. Finally, we find indications of waves that propagate with little attenuation, long distances through sea ice, reflecting off Antarctica.
Africa, Antarctica, Atlantic Ocean, back-projection, beamforming, infragravity waves
2169-9275
Bogiatzis, P.
8fc5767f-51a2-4d3f-aab9-1ee9cfa9272d
Karamitrou, A.
25acd266-3030-4958-b5c5-72d4c6b74caf
Ward Neale, J.
adffc01c-a20f-43ea-a64f-3138a239b9ab
Harmon, N.
10d11a16-b8b0-4132-9354-652e72d8e830
Rychert, C. A.
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Srokosz, M.
f1701d3e-01b3-43d0-8993-9fd523032a79
Bogiatzis, P.
8fc5767f-51a2-4d3f-aab9-1ee9cfa9272d
Karamitrou, A.
25acd266-3030-4958-b5c5-72d4c6b74caf
Ward Neale, J.
adffc01c-a20f-43ea-a64f-3138a239b9ab
Harmon, N.
10d11a16-b8b0-4132-9354-652e72d8e830
Rychert, C. A.
70cf1e3a-58ea-455a-918a-1d570c5e53c5
Srokosz, M.
f1701d3e-01b3-43d0-8993-9fd523032a79

Bogiatzis, P., Karamitrou, A., Ward Neale, J., Harmon, N., Rychert, C. A. and Srokosz, M. (2020) Source regions of infragravity waves recorded at the bottom of the equatorial Atlantic Ocean, using OBS of the PI‐LAB experiment. Journal of Geophysical Research: Oceans, 125 (6), [e2019JC015430]. (doi:10.1029/2019JC015430).

Record type: Article

Abstract

Infragravity waves are generated along coasts, and some small fraction of their energy escapes to the open oceans and propagates with little attenuation. Due to the scarcity of deep‐ocean observations of these waves, the mechanism and the extent of the infragravity waves energy leakage from the coasts remains poorly understood. Understanding the generation and pathways of infragravity wave energy is important among others for understanding the breakup of ice‐shelves, and the contamination of high‐resolution satellite radar altimetry measurements of sea level. We examine data from 37 differential pressure gauges of Ocean Bottom Seismometers (OBS) near the equatorial mid‐Atlantic ridge, deployed during the Passive Imaging of the Lithosphere‐Asthenosphere Boundary (PI‐LAB) experiment. We use the beamforming technique to investigate the incoming directions of infragravity waves. Next, we develop a graph‐theory‐based global back‐projection method of noise cross‐correlation function envelopes, which minimizes the effects of array geometry using an adaptive weighting scheme. This approach allows us to locate the sources of the infragravity energy. We assess our observations by comparing to a global model of infragravity wave heights. Our results reveal strong coherent energy from sources and/or reflected phases at the west coast of Africa and some sources from South America. These energy sources are in good agreement with the global infragravity wave model. In addition, we also observe infragravity waves arriving from North America during specific events that mostly occur during Oct‐Feb 2016. Finally, we find indications of waves that propagate with little attenuation, long distances through sea ice, reflecting off Antarctica.

Text
Source Regions of Infragravity Waves - Accepted Manuscript
Download (3MB)

More information

Accepted/In Press date: 12 May 2020
e-pub ahead of print date: 19 May 2020
Keywords: Africa, Antarctica, Atlantic Ocean, back-projection, beamforming, infragravity waves

Identifiers

Local EPrints ID: 441196
URI: http://eprints.soton.ac.uk/id/eprint/441196
ISSN: 2169-9275
PURE UUID: 8fed795e-e264-4755-8b76-7d2509c992b6
ORCID for P. Bogiatzis: ORCID iD orcid.org/0000-0003-1902-7476
ORCID for N. Harmon: ORCID iD orcid.org/0000-0002-0731-768X

Catalogue record

Date deposited: 04 Jun 2020 16:31
Last modified: 26 Nov 2021 03:10

Export record

Altmetrics

Contributors

Author: P. Bogiatzis ORCID iD
Author: A. Karamitrou
Author: J. Ward Neale
Author: N. Harmon ORCID iD
Author: C. A. Rychert
Author: M. Srokosz

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

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×