Global SST influence on twentieth century NAO variability
Recent studies have suggested that sea surface temperature (SST) is an important source of variability of the North Atlantic Oscillation (NAO). Here, we deal with four basic aspects contributing to this issue: (1) we investigate the characteristic time scales of this oceanic influence; (2) quantify...
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ftoceanrep:oai:oceanrep.geomar.de:6497 2023-05-15T17:28:51+02:00 Global SST influence on twentieth century NAO variability Paeth, H. Latif, Mojib Hense, A. 2003 text https://oceanrep.geomar.de/id/eprint/6497/ https://oceanrep.geomar.de/id/eprint/6497/1/fulltext.pdf https://doi.org/10.1007/s00382-003-0318-4 en eng Springer https://oceanrep.geomar.de/id/eprint/6497/1/fulltext.pdf Paeth, H., Latif, M. and Hense, A. (2003) Global SST influence on twentieth century NAO variability. Climate Dynamics, 21 . pp. 63-75. DOI 10.1007/s00382-003-0318-4 <https://doi.org/10.1007/s00382-003-0318-4>. doi:10.1007/s00382-003-0318-4 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2003 ftoceanrep https://doi.org/10.1007/s00382-003-0318-4 2023-04-07T14:53:01Z Recent studies have suggested that sea surface temperature (SST) is an important source of variability of the North Atlantic Oscillation (NAO). Here, we deal with four basic aspects contributing to this issue: (1) we investigate the characteristic time scales of this oceanic influence; (2) quantify the scale-dependent hindcast potential of the NAO during the twentieth century as derived from SST-driven atmospheric general circulation model (AGCM) ensembles; (3) the relevant oceanic regions are identified, corresponding SST indices are defined and their relationship to the NAO are evaluated by means of cross spectral analysis and (4) our results are compared with long-term coupled control experiments with different ocean models in order to ensure whether the spectral relationship between the SST regions and the NAO is an intrinsic mode of the coupled climate system, involving the deep ocean circulation, rather than an artefact of the unilateral SST forcing. The observed year-to-year NAO fluctuations are barely influenced by the SST. On the decadal time scales the major swings of the observed NAO are well reproduced by various ensembles from the middle of the twentieth century onward, including the negative state in the 1960s and part of the positive trend afterwards. A six-member ECHAM4-T42 ensemble reveals that the SST boundary condition affects 25% of total decadal-mean and interdecadal-trend NAO variability throughout the twentieth century. The most coherent NAO-related SST feature is the well-known North Atlantic tripole. Additional contributions may arise from the southern Pacific and the low-latitude Indian Ocean. The coupled climate model control runs suggest only the North Atlantic SST-NAO relationship as being a true characteristic of the coupled climate system. The coherence and phase spectra of observations and coupled simulations are in excellent agreement, confirming the robustness of this decadal-scale North Atlantic air–sea coupled mode. Article in Journal/Newspaper North Atlantic North Atlantic oscillation OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Indian Pacific Climate Dynamics 21 1 63 75 |
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English |
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Recent studies have suggested that sea surface temperature (SST) is an important source of variability of the North Atlantic Oscillation (NAO). Here, we deal with four basic aspects contributing to this issue: (1) we investigate the characteristic time scales of this oceanic influence; (2) quantify the scale-dependent hindcast potential of the NAO during the twentieth century as derived from SST-driven atmospheric general circulation model (AGCM) ensembles; (3) the relevant oceanic regions are identified, corresponding SST indices are defined and their relationship to the NAO are evaluated by means of cross spectral analysis and (4) our results are compared with long-term coupled control experiments with different ocean models in order to ensure whether the spectral relationship between the SST regions and the NAO is an intrinsic mode of the coupled climate system, involving the deep ocean circulation, rather than an artefact of the unilateral SST forcing. The observed year-to-year NAO fluctuations are barely influenced by the SST. On the decadal time scales the major swings of the observed NAO are well reproduced by various ensembles from the middle of the twentieth century onward, including the negative state in the 1960s and part of the positive trend afterwards. A six-member ECHAM4-T42 ensemble reveals that the SST boundary condition affects 25% of total decadal-mean and interdecadal-trend NAO variability throughout the twentieth century. The most coherent NAO-related SST feature is the well-known North Atlantic tripole. Additional contributions may arise from the southern Pacific and the low-latitude Indian Ocean. The coupled climate model control runs suggest only the North Atlantic SST-NAO relationship as being a true characteristic of the coupled climate system. The coherence and phase spectra of observations and coupled simulations are in excellent agreement, confirming the robustness of this decadal-scale North Atlantic air–sea coupled mode. |
format |
Article in Journal/Newspaper |
author |
Paeth, H. Latif, Mojib Hense, A. |
spellingShingle |
Paeth, H. Latif, Mojib Hense, A. Global SST influence on twentieth century NAO variability |
author_facet |
Paeth, H. Latif, Mojib Hense, A. |
author_sort |
Paeth, H. |
title |
Global SST influence on twentieth century NAO variability |
title_short |
Global SST influence on twentieth century NAO variability |
title_full |
Global SST influence on twentieth century NAO variability |
title_fullStr |
Global SST influence on twentieth century NAO variability |
title_full_unstemmed |
Global SST influence on twentieth century NAO variability |
title_sort |
global sst influence on twentieth century nao variability |
publisher |
Springer |
publishDate |
2003 |
url |
https://oceanrep.geomar.de/id/eprint/6497/ https://oceanrep.geomar.de/id/eprint/6497/1/fulltext.pdf https://doi.org/10.1007/s00382-003-0318-4 |
geographic |
Indian Pacific |
geographic_facet |
Indian Pacific |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
https://oceanrep.geomar.de/id/eprint/6497/1/fulltext.pdf Paeth, H., Latif, M. and Hense, A. (2003) Global SST influence on twentieth century NAO variability. Climate Dynamics, 21 . pp. 63-75. DOI 10.1007/s00382-003-0318-4 <https://doi.org/10.1007/s00382-003-0318-4>. doi:10.1007/s00382-003-0318-4 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1007/s00382-003-0318-4 |
container_title |
Climate Dynamics |
container_volume |
21 |
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1 |
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63 |
op_container_end_page |
75 |
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1766121984507248640 |