The variability of the subantarctic front and the Southern Hemisphere atmospheric jet
Abstract The latitudinal variations of the Subantarctic Front (SAF) and Southern Hemisphere atmospheric jet were investigated for the period of 1993-2016. Zonal wind velocity, sea surface height and temperature data were used to identify these features over the South Atlantic, South Pacific and Indi...
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ftdoajarticles:oai:doaj.org/article:da08d283303f4eb28b5b5ad011e5db1d 2023-05-15T13:32:08+02:00 The variability of the subantarctic front and the Southern Hemisphere atmospheric jet João L. E. Simon Regina R. Rodrigues 2019-12-01T00:00:00Z https://doi.org/10.1590/s1679-87592019025606712 https://doaj.org/article/da08d283303f4eb28b5b5ad011e5db1d EN eng Universidade de São Paulo http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-87592019000100409&tlng=en http://www.scielo.br/pdf/bjoce/v67/1679-8759-bjoce-67-e19256.pdf https://doaj.org/toc/1982-436X 1982-436X doi:10.1590/s1679-87592019025606712 https://doaj.org/article/da08d283303f4eb28b5b5ad011e5db1d Brazilian Journal of Oceanography, Vol 67 (2019) Subantarctic front Atmospheric jet Southern hemisphere Oceanography GC1-1581 article 2019 ftdoajarticles https://doi.org/10.1590/s1679-87592019025606712 2022-12-31T14:10:37Z Abstract The latitudinal variations of the Subantarctic Front (SAF) and Southern Hemisphere atmospheric jet were investigated for the period of 1993-2016. Zonal wind velocity, sea surface height and temperature data were used to identify these features over the South Atlantic, South Pacific and Indian Oceans individually. During this period, the atmospheric jet migrated poleward 0.34°S decade-1 in the Atlantic, 0.28°S decade-1 in the Pacific and 0.14°S decade-1 in the Indian oceans. Previous works have shown that the poleward trend is due to the expansion of the tropical belt as a consequence of greenhouse gas increase and cooling of polar stratosphere due to ozone depletion. In addition the atmospheric jet strengthen in all three basins. The SAF represents the Antarctic Circumpolar Current northern boundary and was observed in average at 46.3°S (±0.5°) in the Atlantic, 54.3°S (±0.3°) in the Pacific and 46.6°S (±0.5°) in Indian Oceans. The SAF shows a poleward migration of 0.46°S decade-1 in the Atlantic, 0.20°S decade-1 in the Pacific and 0.27°S decade-1 in the Indian Oceans, which is attributed to the sea level increasing in the Southern Hemisphere due to thermal expansion. The SAF poleward trend is consistent with the positive trend of the Southern Annular Mode during the studied period. Moreover, the jet position is statistically significant correlated to the SAF position in each ocean basin. However, the coefficients are weak: +0.22 for the Atlantic, +0.17 for the Pacific and +0.21 for the Indian oceans. The latitudinal displacement of the SAF in the Pacific is inversely proportional to the El Niño-Southern Oscillations (ENSO). During El Niño years the SAF tend to be more poleward and during La Niña years more equatorward, with maximum correlation of 0.56, with ENSO leading by three months. Article in Journal/Newspaper Antarc* Antarctic Directory of Open Access Journals: DOAJ Articles Antarctic Indian Pacific The Antarctic Brazilian Journal of Oceanography 67 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Subantarctic front Atmospheric jet Southern hemisphere Oceanography GC1-1581 |
spellingShingle |
Subantarctic front Atmospheric jet Southern hemisphere Oceanography GC1-1581 João L. E. Simon Regina R. Rodrigues The variability of the subantarctic front and the Southern Hemisphere atmospheric jet |
topic_facet |
Subantarctic front Atmospheric jet Southern hemisphere Oceanography GC1-1581 |
description |
Abstract The latitudinal variations of the Subantarctic Front (SAF) and Southern Hemisphere atmospheric jet were investigated for the period of 1993-2016. Zonal wind velocity, sea surface height and temperature data were used to identify these features over the South Atlantic, South Pacific and Indian Oceans individually. During this period, the atmospheric jet migrated poleward 0.34°S decade-1 in the Atlantic, 0.28°S decade-1 in the Pacific and 0.14°S decade-1 in the Indian oceans. Previous works have shown that the poleward trend is due to the expansion of the tropical belt as a consequence of greenhouse gas increase and cooling of polar stratosphere due to ozone depletion. In addition the atmospheric jet strengthen in all three basins. The SAF represents the Antarctic Circumpolar Current northern boundary and was observed in average at 46.3°S (±0.5°) in the Atlantic, 54.3°S (±0.3°) in the Pacific and 46.6°S (±0.5°) in Indian Oceans. The SAF shows a poleward migration of 0.46°S decade-1 in the Atlantic, 0.20°S decade-1 in the Pacific and 0.27°S decade-1 in the Indian Oceans, which is attributed to the sea level increasing in the Southern Hemisphere due to thermal expansion. The SAF poleward trend is consistent with the positive trend of the Southern Annular Mode during the studied period. Moreover, the jet position is statistically significant correlated to the SAF position in each ocean basin. However, the coefficients are weak: +0.22 for the Atlantic, +0.17 for the Pacific and +0.21 for the Indian oceans. The latitudinal displacement of the SAF in the Pacific is inversely proportional to the El Niño-Southern Oscillations (ENSO). During El Niño years the SAF tend to be more poleward and during La Niña years more equatorward, with maximum correlation of 0.56, with ENSO leading by three months. |
format |
Article in Journal/Newspaper |
author |
João L. E. Simon Regina R. Rodrigues |
author_facet |
João L. E. Simon Regina R. Rodrigues |
author_sort |
João L. E. Simon |
title |
The variability of the subantarctic front and the Southern Hemisphere atmospheric jet |
title_short |
The variability of the subantarctic front and the Southern Hemisphere atmospheric jet |
title_full |
The variability of the subantarctic front and the Southern Hemisphere atmospheric jet |
title_fullStr |
The variability of the subantarctic front and the Southern Hemisphere atmospheric jet |
title_full_unstemmed |
The variability of the subantarctic front and the Southern Hemisphere atmospheric jet |
title_sort |
variability of the subantarctic front and the southern hemisphere atmospheric jet |
publisher |
Universidade de São Paulo |
publishDate |
2019 |
url |
https://doi.org/10.1590/s1679-87592019025606712 https://doaj.org/article/da08d283303f4eb28b5b5ad011e5db1d |
geographic |
Antarctic Indian Pacific The Antarctic |
geographic_facet |
Antarctic Indian Pacific The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Brazilian Journal of Oceanography, Vol 67 (2019) |
op_relation |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-87592019000100409&tlng=en http://www.scielo.br/pdf/bjoce/v67/1679-8759-bjoce-67-e19256.pdf https://doaj.org/toc/1982-436X 1982-436X doi:10.1590/s1679-87592019025606712 https://doaj.org/article/da08d283303f4eb28b5b5ad011e5db1d |
op_doi |
https://doi.org/10.1590/s1679-87592019025606712 |
container_title |
Brazilian Journal of Oceanography |
container_volume |
67 |
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1766024495456321536 |