Spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures
The Southern Annular Mode (SAM) is the predominant atmospheric variability mode in the Southern Hemisphere. In this paper, we present the spatial variability results of the SAM pattern for the period 1979–2018. The SAM‐intrinsic pattern variability analysis is based on the principal component analys...
Published in: | Journal of Geophysical Research: Atmospheres |
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ftunivaugsburg:oai:uni-augsburg.opus-bayern.de:83448 2023-05-15T13:42:36+02:00 Spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures Wachter, Paul Beck, Christoph Philipp, Andreas Höppner, Kathrin Jacobeit, Jucundus 2020-12-05 application/pdf https://opus.bibliothek.uni-augsburg.de/opus4/frontdoor/index/index/docId/83448 https://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-834485 https://doi.org/10.1029/2020JD033818 https://opus.bibliothek.uni-augsburg.de/opus4/files/83448/JGRD_JGRD56657.pdf eng eng https://opus.bibliothek.uni-augsburg.de/opus4/frontdoor/index/index/docId/83448 urn:nbn:de:bvb:384-opus4-834485 https://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-834485 https://doi.org/10.1029/2020JD033818 https://opus.bibliothek.uni-augsburg.de/opus4/files/83448/JGRD_JGRD56657.pdf https://creativecommons.org/licenses/by/4.0/deed.de CC-BY 4.0: Creative Commons: Namensnennung (mit Print on Demand) info:eu-repo/semantics/openAccess CC-BY ddc:550 article doc-type:article 2020 ftunivaugsburg https://doi.org/10.1029/2020JD033818 2022-11-29T20:34:36Z The Southern Annular Mode (SAM) is the predominant atmospheric variability mode in the Southern Hemisphere. In this paper, we present the spatial variability results of the SAM pattern for the period 1979–2018. The SAM‐intrinsic pattern variability analysis is based on the principal component analysis (PCA), which is carried out for the ERA‐Interim 500 hPa geopotential height (GPH) data set. A spatiotemporally resolved data set of SAM pattern maps (PCA loadings) is derived by projecting monthly shifted sub‐sequences of SAM index values (PCA scores) on the corresponding GPH anomalies. The dominant SAM structure within single pattern fields is mapped automatically and can be interpreted as the Southern Hemisphere polar front. This data set allows an analysis of the geographical positions of the characteristic circumpolar SAM structure over four decades and shows considerable variability over space and time. Five different states of SAM patterns, which are associated with characteristic circulation anomalies during different phases of the study period, are identified. Station‐based Antarctic temperature anomalies can be synoptically explained by these circulation anomalies. The overall latitudinal trend of the SAM pattern indicates an intensification of the meridional structure, especially over the East Antarctic Southern Ocean. Furthermore, we show that the SAM pattern variability is significantly correlated with the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation. Composites of 500 hPa GPH anomalies during the positive and negative phases of the respective indices indicate teleconnections with Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation, and this can explain latitudinal trends of the SAM pattern. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Augsburg University Publication Server (OPUS) Antarctic Pacific Southern Ocean Journal of Geophysical Research: Atmospheres 125 23 |
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Augsburg University Publication Server (OPUS) |
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ftunivaugsburg |
language |
English |
topic |
ddc:550 |
spellingShingle |
ddc:550 Wachter, Paul Beck, Christoph Philipp, Andreas Höppner, Kathrin Jacobeit, Jucundus Spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures |
topic_facet |
ddc:550 |
description |
The Southern Annular Mode (SAM) is the predominant atmospheric variability mode in the Southern Hemisphere. In this paper, we present the spatial variability results of the SAM pattern for the period 1979–2018. The SAM‐intrinsic pattern variability analysis is based on the principal component analysis (PCA), which is carried out for the ERA‐Interim 500 hPa geopotential height (GPH) data set. A spatiotemporally resolved data set of SAM pattern maps (PCA loadings) is derived by projecting monthly shifted sub‐sequences of SAM index values (PCA scores) on the corresponding GPH anomalies. The dominant SAM structure within single pattern fields is mapped automatically and can be interpreted as the Southern Hemisphere polar front. This data set allows an analysis of the geographical positions of the characteristic circumpolar SAM structure over four decades and shows considerable variability over space and time. Five different states of SAM patterns, which are associated with characteristic circulation anomalies during different phases of the study period, are identified. Station‐based Antarctic temperature anomalies can be synoptically explained by these circulation anomalies. The overall latitudinal trend of the SAM pattern indicates an intensification of the meridional structure, especially over the East Antarctic Southern Ocean. Furthermore, we show that the SAM pattern variability is significantly correlated with the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation. Composites of 500 hPa GPH anomalies during the positive and negative phases of the respective indices indicate teleconnections with Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation, and this can explain latitudinal trends of the SAM pattern. |
format |
Article in Journal/Newspaper |
author |
Wachter, Paul Beck, Christoph Philipp, Andreas Höppner, Kathrin Jacobeit, Jucundus |
author_facet |
Wachter, Paul Beck, Christoph Philipp, Andreas Höppner, Kathrin Jacobeit, Jucundus |
author_sort |
Wachter, Paul |
title |
Spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures |
title_short |
Spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures |
title_full |
Spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures |
title_fullStr |
Spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures |
title_full_unstemmed |
Spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures |
title_sort |
spatiotemporal variability of the southern annular mode and its influence on antarctic surface temperatures |
publishDate |
2020 |
url |
https://opus.bibliothek.uni-augsburg.de/opus4/frontdoor/index/index/docId/83448 https://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-834485 https://doi.org/10.1029/2020JD033818 https://opus.bibliothek.uni-augsburg.de/opus4/files/83448/JGRD_JGRD56657.pdf |
geographic |
Antarctic Pacific Southern Ocean |
geographic_facet |
Antarctic Pacific Southern Ocean |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
https://opus.bibliothek.uni-augsburg.de/opus4/frontdoor/index/index/docId/83448 urn:nbn:de:bvb:384-opus4-834485 https://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-834485 https://doi.org/10.1029/2020JD033818 https://opus.bibliothek.uni-augsburg.de/opus4/files/83448/JGRD_JGRD56657.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/deed.de CC-BY 4.0: Creative Commons: Namensnennung (mit Print on Demand) info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1029/2020JD033818 |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
125 |
container_issue |
23 |
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1766169978139049984 |