Formation and propagation of temperature anomalies along the North Atlantic Current
A general circulation ocean model has been used to study the formation and propagation mechanisms of North Atlantic Oscillation (NAO)-generated temperature anomalies along the pathway of the North Atlantic Current (NAC). The NAO-like wind forcing generates temperature anomalies in the upper 440 m th...
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ftoceanrep:oai:oceanrep.geomar.de:2840 2023-05-15T17:25:17+02:00 Formation and propagation of temperature anomalies along the North Atlantic Current Krahmann, Gerd Visbeck, Martin Reverdin, G. 2001 text https://oceanrep.geomar.de/id/eprint/2840/ https://oceanrep.geomar.de/id/eprint/2840/1/Krahmann.pdf https://doi.org/10.1175/1520-0485(2001)031<1287:FAPOTA>2.0.CO;2 en eng AMS (American Meteorological Society) https://oceanrep.geomar.de/id/eprint/2840/1/Krahmann.pdf Krahmann, G. , Visbeck, M. and Reverdin, G. (2001) Formation and propagation of temperature anomalies along the North Atlantic Current. Open Access Journal of Physical Oceanography, 31 . pp. 1287-1303. DOI 10.1175/1520-0485(2001)031<1287:FAPOTA>2.0.CO;2 <https://doi.org/10.1175/1520-0485%282001%29031%3C1287%3AFAPOTA%3E2.0.CO%3B2>. doi:10.1175/1520-0485(2001)031<1287:FAPOTA>2.0.CO;2 info:eu-repo/semantics/openAccess Article PeerReviewed 2001 ftoceanrep https://doi.org/10.1175/1520-0485(2001)031<1287:FAPOTA>2.0.CO;2 2023-04-07T14:46:35Z A general circulation ocean model has been used to study the formation and propagation mechanisms of North Atlantic Oscillation (NAO)-generated temperature anomalies along the pathway of the North Atlantic Current (NAC). The NAO-like wind forcing generates temperature anomalies in the upper 440 m that propagate along the pathway of the NAC in general agreement with the observations. The analysis of individual components of the ocean heat budget reveals that the anomalies are primarily generated by the wind stress anomaly-induced oceanic heat transport divergence. After their generation they are advected with the mean current. Surface heat flux anomalies account for only one-third of the total temperature changes. Along the pathway of the NAC temperature anomalies of opposite signs are formed in the first and second halves of the pathway, a pattern called here the North Atlantic dipole (NAD). The response of the ocean depends fundamentally on Rt = (L/υ)/τ, the ratio between the time it takes for anomalies to propagate along the NAC [(L/υ) 10 years] compared to the forcing period τ. The authors find that for NAO periods shorter than 4 years (Rt > 1) the response in the subpolar region is mainly determined by the local forcing. For NAO periods longer than 32 years (Rt < 1); however, the SST anomalies in the northeastern part of the NAD become controlled by ocean advection. In the subpolar region maximal amplitudes of the temperature response are found for intermediate (decadal) periods (Rt 1) where the propagation of temperature anomalies constructively interferes with the local forcing. A comparison of the NAO-generated propagating temperature anomalies with those found in observations will be discussed. Article in Journal/Newspaper north atlantic current North Atlantic North Atlantic oscillation OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
A general circulation ocean model has been used to study the formation and propagation mechanisms of North Atlantic Oscillation (NAO)-generated temperature anomalies along the pathway of the North Atlantic Current (NAC). The NAO-like wind forcing generates temperature anomalies in the upper 440 m that propagate along the pathway of the NAC in general agreement with the observations. The analysis of individual components of the ocean heat budget reveals that the anomalies are primarily generated by the wind stress anomaly-induced oceanic heat transport divergence. After their generation they are advected with the mean current. Surface heat flux anomalies account for only one-third of the total temperature changes. Along the pathway of the NAC temperature anomalies of opposite signs are formed in the first and second halves of the pathway, a pattern called here the North Atlantic dipole (NAD). The response of the ocean depends fundamentally on Rt = (L/υ)/τ, the ratio between the time it takes for anomalies to propagate along the NAC [(L/υ) 10 years] compared to the forcing period τ. The authors find that for NAO periods shorter than 4 years (Rt > 1) the response in the subpolar region is mainly determined by the local forcing. For NAO periods longer than 32 years (Rt < 1); however, the SST anomalies in the northeastern part of the NAD become controlled by ocean advection. In the subpolar region maximal amplitudes of the temperature response are found for intermediate (decadal) periods (Rt 1) where the propagation of temperature anomalies constructively interferes with the local forcing. A comparison of the NAO-generated propagating temperature anomalies with those found in observations will be discussed. |
format |
Article in Journal/Newspaper |
author |
Krahmann, Gerd Visbeck, Martin Reverdin, G. |
spellingShingle |
Krahmann, Gerd Visbeck, Martin Reverdin, G. Formation and propagation of temperature anomalies along the North Atlantic Current |
author_facet |
Krahmann, Gerd Visbeck, Martin Reverdin, G. |
author_sort |
Krahmann, Gerd |
title |
Formation and propagation of temperature anomalies along the North Atlantic Current |
title_short |
Formation and propagation of temperature anomalies along the North Atlantic Current |
title_full |
Formation and propagation of temperature anomalies along the North Atlantic Current |
title_fullStr |
Formation and propagation of temperature anomalies along the North Atlantic Current |
title_full_unstemmed |
Formation and propagation of temperature anomalies along the North Atlantic Current |
title_sort |
formation and propagation of temperature anomalies along the north atlantic current |
publisher |
AMS (American Meteorological Society) |
publishDate |
2001 |
url |
https://oceanrep.geomar.de/id/eprint/2840/ https://oceanrep.geomar.de/id/eprint/2840/1/Krahmann.pdf https://doi.org/10.1175/1520-0485(2001)031<1287:FAPOTA>2.0.CO;2 |
genre |
north atlantic current North Atlantic North Atlantic oscillation |
genre_facet |
north atlantic current North Atlantic North Atlantic oscillation |
op_relation |
https://oceanrep.geomar.de/id/eprint/2840/1/Krahmann.pdf Krahmann, G. , Visbeck, M. and Reverdin, G. (2001) Formation and propagation of temperature anomalies along the North Atlantic Current. Open Access Journal of Physical Oceanography, 31 . pp. 1287-1303. DOI 10.1175/1520-0485(2001)031<1287:FAPOTA>2.0.CO;2 <https://doi.org/10.1175/1520-0485%282001%29031%3C1287%3AFAPOTA%3E2.0.CO%3B2>. doi:10.1175/1520-0485(2001)031<1287:FAPOTA>2.0.CO;2 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/1520-0485(2001)031<1287:FAPOTA>2.0.CO;2 |
_version_ |
1766116666971783168 |