Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis.
Atmospheric gravity waves play a key role in the transfer of energy and momentum between layers of the Earth's atmosphere. However, nearly all Global Circulation Models (GCMs) seriously under-represent the momentum fluxes of gravity waves at latitudes near 60° S. This can result in modelled win...
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Copernicus GmbH
2019
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ftnerc:oai:nora.nerc.ac.uk:526118 2023-05-15T13:41:44+02:00 Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. Hindley, Neil P. Wright, Corwin J. Smith, Nathan D. Hoffman, Lars Holt, Laura A. Alexander, M. Joan Moffat-Griffin, Tracy Mitchell, Nicholas J. 2019-12-17 text http://nora.nerc.ac.uk/id/eprint/526118/ https://nora.nerc.ac.uk/id/eprint/526118/1/acp-19-15377-2019.pdf https://www.atmos-chem-phys.net/19/15377/2019/acp-19-15377-2019.pdf en eng Copernicus GmbH https://nora.nerc.ac.uk/id/eprint/526118/1/acp-19-15377-2019.pdf Hindley, Neil P.; Wright, Corwin J.; Smith, Nathan D.; Hoffman, Lars; Holt, Laura A.; Alexander, M. Joan; Moffat-Griffin, Tracy orcid:0000-0002-9670-6715 Mitchell, Nicholas J. 2019 Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. Atmospheric Chemistry and Physics, 19 (24). 15377-15414. https://doi.org/10.5194/acp-19-15377-2019 <https://doi.org/10.5194/acp-19-15377-2019> cc_by_4 CC-BY Publication - Article PeerReviewed 2019 ftnerc https://doi.org/10.5194/acp-19-15377-2019 2023-02-04T19:49:47Z Atmospheric gravity waves play a key role in the transfer of energy and momentum between layers of the Earth's atmosphere. However, nearly all Global Circulation Models (GCMs) seriously under-represent the momentum fluxes of gravity waves at latitudes near 60° S. This can result in modelled winter stratospheres that are unrealistically cold – a significant bias known as the "cold-pole problem". There is thus a need for measurements of gravity-wave fluxes near 60S to test and constrain GCMs. Such measurements are notoriously difficult, because they require 3-D observations of wave properties if the fluxes are to be estimated without using significant limiting assumptions. Here we use 3-D satellite measurements of stratospheric gravity waves from NASA's AIRS/Aqua instrument. We present the first extended application of a 3-D Stockwell transform (3DST) method to determine localised gravity-wave amplitudes, wavelengths and directions of propagation around the entire region of the Southern Ocean near 60° S during austral winter 2010. We first validate our method using a synthetic wave field and two case studies of real gravity waves over the Southern Andes and the island of South Georgia. A new technique to overcome wave amplitude attenuation problems in previous methods is also presented. We then characterise large-scale gravity-wave occurrence frequencies, directional momentum fluxes and short-timescale intermittency over the entire Southern Ocean. Our results show that highest wave-occurrence frequencies, amplitudes and momentum fluxes are observed in the stratosphere over the mountains of the Southern Andes and Antarctic Peninsula. However, we find that around 60–80 % of total zonal-mean momentum flux is located over the open Southern Ocean during June–August, where a large "belt" of increased wave-occurrence frequencies, amplitudes and fluxes is observed. Our results also suggest significant short-timescale variability of fluxes from both orographic and non-orographic sources in the region. A particularly ... Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Southern Ocean Natural Environment Research Council: NERC Open Research Archive Antarctic Southern Ocean Antarctic Peninsula Austral Atmospheric Chemistry and Physics 19 24 15377 15414 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Atmospheric gravity waves play a key role in the transfer of energy and momentum between layers of the Earth's atmosphere. However, nearly all Global Circulation Models (GCMs) seriously under-represent the momentum fluxes of gravity waves at latitudes near 60° S. This can result in modelled winter stratospheres that are unrealistically cold – a significant bias known as the "cold-pole problem". There is thus a need for measurements of gravity-wave fluxes near 60S to test and constrain GCMs. Such measurements are notoriously difficult, because they require 3-D observations of wave properties if the fluxes are to be estimated without using significant limiting assumptions. Here we use 3-D satellite measurements of stratospheric gravity waves from NASA's AIRS/Aqua instrument. We present the first extended application of a 3-D Stockwell transform (3DST) method to determine localised gravity-wave amplitudes, wavelengths and directions of propagation around the entire region of the Southern Ocean near 60° S during austral winter 2010. We first validate our method using a synthetic wave field and two case studies of real gravity waves over the Southern Andes and the island of South Georgia. A new technique to overcome wave amplitude attenuation problems in previous methods is also presented. We then characterise large-scale gravity-wave occurrence frequencies, directional momentum fluxes and short-timescale intermittency over the entire Southern Ocean. Our results show that highest wave-occurrence frequencies, amplitudes and momentum fluxes are observed in the stratosphere over the mountains of the Southern Andes and Antarctic Peninsula. However, we find that around 60–80 % of total zonal-mean momentum flux is located over the open Southern Ocean during June–August, where a large "belt" of increased wave-occurrence frequencies, amplitudes and fluxes is observed. Our results also suggest significant short-timescale variability of fluxes from both orographic and non-orographic sources in the region. A particularly ... |
format |
Article in Journal/Newspaper |
author |
Hindley, Neil P. Wright, Corwin J. Smith, Nathan D. Hoffman, Lars Holt, Laura A. Alexander, M. Joan Moffat-Griffin, Tracy Mitchell, Nicholas J. |
spellingShingle |
Hindley, Neil P. Wright, Corwin J. Smith, Nathan D. Hoffman, Lars Holt, Laura A. Alexander, M. Joan Moffat-Griffin, Tracy Mitchell, Nicholas J. Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. |
author_facet |
Hindley, Neil P. Wright, Corwin J. Smith, Nathan D. Hoffman, Lars Holt, Laura A. Alexander, M. Joan Moffat-Griffin, Tracy Mitchell, Nicholas J. |
author_sort |
Hindley, Neil P. |
title |
Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. |
title_short |
Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. |
title_full |
Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. |
title_fullStr |
Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. |
title_full_unstemmed |
Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. |
title_sort |
gravity waves in the winter stratosphere over the southern ocean: high-resolution satellite observations and 3-d spectral analysis. |
publisher |
Copernicus GmbH |
publishDate |
2019 |
url |
http://nora.nerc.ac.uk/id/eprint/526118/ https://nora.nerc.ac.uk/id/eprint/526118/1/acp-19-15377-2019.pdf https://www.atmos-chem-phys.net/19/15377/2019/acp-19-15377-2019.pdf |
geographic |
Antarctic Southern Ocean Antarctic Peninsula Austral |
geographic_facet |
Antarctic Southern Ocean Antarctic Peninsula Austral |
genre |
Antarc* Antarctic Antarctic Peninsula Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Southern Ocean |
op_relation |
https://nora.nerc.ac.uk/id/eprint/526118/1/acp-19-15377-2019.pdf Hindley, Neil P.; Wright, Corwin J.; Smith, Nathan D.; Hoffman, Lars; Holt, Laura A.; Alexander, M. Joan; Moffat-Griffin, Tracy orcid:0000-0002-9670-6715 Mitchell, Nicholas J. 2019 Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis. Atmospheric Chemistry and Physics, 19 (24). 15377-15414. https://doi.org/10.5194/acp-19-15377-2019 <https://doi.org/10.5194/acp-19-15377-2019> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/acp-19-15377-2019 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
19 |
container_issue |
24 |
container_start_page |
15377 |
op_container_end_page |
15414 |
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1766156302318305280 |