Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations
Stratospheric gravity waves from small-scale orographic sources are currently not well-represented in general circulation models. This may be a reason why many simulations have difficulty reproducing the dynamical behavior of the Southern Hemisphere polar vortex in a realistic manner. Here we discus...
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ftdoajarticles:oai:doaj.org/article:e052fd716dd34285ae36fa421b37579a 2023-05-15T13:47:24+02:00 Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations L. Hoffmann A. W. Grimsdell M. J. Alexander 2016-07-01T00:00:00Z https://doi.org/10.5194/acp-16-9381-2016 https://doaj.org/article/e052fd716dd34285ae36fa421b37579a EN eng Copernicus Publications https://www.atmos-chem-phys.net/16/9381/2016/acp-16-9381-2016.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-16-9381-2016 1680-7316 1680-7324 https://doaj.org/article/e052fd716dd34285ae36fa421b37579a Atmospheric Chemistry and Physics, Vol 16, Pp 9381-9397 (2016) Physics QC1-999 Chemistry QD1-999 article 2016 ftdoajarticles https://doi.org/10.5194/acp-16-9381-2016 2022-12-31T01:36:25Z Stratospheric gravity waves from small-scale orographic sources are currently not well-represented in general circulation models. This may be a reason why many simulations have difficulty reproducing the dynamical behavior of the Southern Hemisphere polar vortex in a realistic manner. Here we discuss a 12-year record (2003–2014) of stratospheric gravity wave activity at Southern Hemisphere orographic hotspots as observed by the Atmospheric InfraRed Sounder (AIRS) aboard the National Aeronautics and Space Administration's (NASA) Aqua satellite. We introduce a simple and effective approach, referred to as the “two-box method”, to detect gravity wave activity from infrared nadir sounder measurements and to discriminate between gravity waves from orographic and other sources. From austral mid-fall to mid-spring (April–October) the contributions of orographic sources to the observed gravity wave occurrence frequencies were found to be largest for the Andes (90 %), followed by the Antarctic Peninsula (76 %), Kerguelen Islands (73 %), Tasmania (70 %), New Zealand (67 %), Heard Island (60 %), and other hotspots (24–54 %). Mountain wave activity was found to be closely correlated with peak terrain altitudes, and with zonal winds in the lower troposphere and mid-stratosphere. We propose a simple model to predict the occurrence of mountain wave events in the AIRS observations using zonal wind thresholds at 3 and 750 hPa. The model has significant predictive skill for hotspots where gravity wave activity is primarily due to orographic sources. It typically reproduces seasonal variations of the mountain wave occurrence frequencies at the Antarctic Peninsula and Kerguelen Islands from near zero to over 60 % with mean absolute errors of 4–5 percentage points. The prediction model can be used to disentangle upper level wind effects on observed occurrence frequencies from low-level source and other influences. The data and methods presented here can help to identify interesting case studies in the vast amount of AIRS data, which ... Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Heard Island Kerguelen Islands Directory of Open Access Journals: DOAJ Articles Antarctic Antarctic Peninsula Austral Heard Island Kerguelen Kerguelen Islands New Zealand The Antarctic Atmospheric Chemistry and Physics 16 14 9381 9397 |
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Directory of Open Access Journals: DOAJ Articles |
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language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 L. Hoffmann A. W. Grimsdell M. J. Alexander Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
Stratospheric gravity waves from small-scale orographic sources are currently not well-represented in general circulation models. This may be a reason why many simulations have difficulty reproducing the dynamical behavior of the Southern Hemisphere polar vortex in a realistic manner. Here we discuss a 12-year record (2003–2014) of stratospheric gravity wave activity at Southern Hemisphere orographic hotspots as observed by the Atmospheric InfraRed Sounder (AIRS) aboard the National Aeronautics and Space Administration's (NASA) Aqua satellite. We introduce a simple and effective approach, referred to as the “two-box method”, to detect gravity wave activity from infrared nadir sounder measurements and to discriminate between gravity waves from orographic and other sources. From austral mid-fall to mid-spring (April–October) the contributions of orographic sources to the observed gravity wave occurrence frequencies were found to be largest for the Andes (90 %), followed by the Antarctic Peninsula (76 %), Kerguelen Islands (73 %), Tasmania (70 %), New Zealand (67 %), Heard Island (60 %), and other hotspots (24–54 %). Mountain wave activity was found to be closely correlated with peak terrain altitudes, and with zonal winds in the lower troposphere and mid-stratosphere. We propose a simple model to predict the occurrence of mountain wave events in the AIRS observations using zonal wind thresholds at 3 and 750 hPa. The model has significant predictive skill for hotspots where gravity wave activity is primarily due to orographic sources. It typically reproduces seasonal variations of the mountain wave occurrence frequencies at the Antarctic Peninsula and Kerguelen Islands from near zero to over 60 % with mean absolute errors of 4–5 percentage points. The prediction model can be used to disentangle upper level wind effects on observed occurrence frequencies from low-level source and other influences. The data and methods presented here can help to identify interesting case studies in the vast amount of AIRS data, which ... |
format |
Article in Journal/Newspaper |
author |
L. Hoffmann A. W. Grimsdell M. J. Alexander |
author_facet |
L. Hoffmann A. W. Grimsdell M. J. Alexander |
author_sort |
L. Hoffmann |
title |
Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations |
title_short |
Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations |
title_full |
Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations |
title_fullStr |
Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations |
title_full_unstemmed |
Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations |
title_sort |
stratospheric gravity waves at southern hemisphere orographic hotspots: 2003–2014 airs/aqua observations |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/acp-16-9381-2016 https://doaj.org/article/e052fd716dd34285ae36fa421b37579a |
geographic |
Antarctic Antarctic Peninsula Austral Heard Island Kerguelen Kerguelen Islands New Zealand The Antarctic |
geographic_facet |
Antarctic Antarctic Peninsula Austral Heard Island Kerguelen Kerguelen Islands New Zealand The Antarctic |
genre |
Antarc* Antarctic Antarctic Peninsula Heard Island Kerguelen Islands |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Heard Island Kerguelen Islands |
op_source |
Atmospheric Chemistry and Physics, Vol 16, Pp 9381-9397 (2016) |
op_relation |
https://www.atmos-chem-phys.net/16/9381/2016/acp-16-9381-2016.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-16-9381-2016 1680-7316 1680-7324 https://doaj.org/article/e052fd716dd34285ae36fa421b37579a |
op_doi |
https://doi.org/10.5194/acp-16-9381-2016 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
16 |
container_issue |
14 |
container_start_page |
9381 |
op_container_end_page |
9397 |
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1766247066320764928 |