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Signatures of the 1976-77 regime shift in the North Pacific revealed by statistical analysis

Signatures of the 1976-77 regime shift in the North Pacific revealed by statistical analysis
Signatures of the 1976-77 regime shift in the North Pacific revealed by statistical analysis
Regime shifts are abrupt changes in an ecosystem that may propagate through multiple trophic levels and have pronounced effects on the biotic and abiotic environment, potentially resulting in ecosystem reorganization. There are multiple mechanisms that could cause such abrupt events including natural and anthropogenic factors. In the North Pacific a major shift in the physics of the system, including a sudden increase in sea surface temperature, was reported in 1977 with a prominent biological response in the lower trophic levels and subsequent effects on the fisheries and economy of the region. Here we investigate the statistics of physical processes that could have triggered and maintained the late 1970’s shift. The hypothesis of an extreme sea level pressure event abruptly changing the oceanic conditions in winter 1976-1977, which was maintained by long-term changes in air-sea interaction processes, is tested. Using a novel statistical and dynamical approach, we show the occurrence of an extreme atmospheric event, specifically a persistent Aleutian Low during winter 1976-77, which constitutes a substantial part of the triggering mechanism of the regime shift. Subsequent sudden changes in the net heat flux occurred in the western North Pacific, particularly in the Kuroshio Extension region, which contributed to the maintenance of the new regime.
2169-9275
4388-4397
Giamalaki, Aikaterini
5e775077-5afb-4ed0-82ad-346af4815d4f
Beaulieu, Claudie
13ae2c11-ebfe-48d9-bda9-122cd013c021
Faranda, Davide
db78a1c6-b6f5-4d1d-bac2-f425b5388265
Henson, Stephanie
d6532e17-a65b-4d7b-9ee3-755ecb565c19
Josey, Simon
2252ab7f-5cd2-49fd-a951-aece44553d93
Martin, Adrian
9d0d480d-9b3c-44c2-aafe-bb980ed98a6d
Giamalaki, Aikaterini
5e775077-5afb-4ed0-82ad-346af4815d4f
Beaulieu, Claudie
13ae2c11-ebfe-48d9-bda9-122cd013c021
Faranda, Davide
db78a1c6-b6f5-4d1d-bac2-f425b5388265
Henson, Stephanie
d6532e17-a65b-4d7b-9ee3-755ecb565c19
Josey, Simon
2252ab7f-5cd2-49fd-a951-aece44553d93
Martin, Adrian
9d0d480d-9b3c-44c2-aafe-bb980ed98a6d

Giamalaki, Aikaterini, Beaulieu, Claudie, Faranda, Davide, Henson, Stephanie, Josey, Simon and Martin, Adrian (2018) Signatures of the 1976-77 regime shift in the North Pacific revealed by statistical analysis. Journal of Geophysical Research: Oceans, 123 (6), 4388-4397. (doi:10.1029/2017JC013718).

Record type: Article

Abstract

Regime shifts are abrupt changes in an ecosystem that may propagate through multiple trophic levels and have pronounced effects on the biotic and abiotic environment, potentially resulting in ecosystem reorganization. There are multiple mechanisms that could cause such abrupt events including natural and anthropogenic factors. In the North Pacific a major shift in the physics of the system, including a sudden increase in sea surface temperature, was reported in 1977 with a prominent biological response in the lower trophic levels and subsequent effects on the fisheries and economy of the region. Here we investigate the statistics of physical processes that could have triggered and maintained the late 1970’s shift. The hypothesis of an extreme sea level pressure event abruptly changing the oceanic conditions in winter 1976-1977, which was maintained by long-term changes in air-sea interaction processes, is tested. Using a novel statistical and dynamical approach, we show the occurrence of an extreme atmospheric event, specifically a persistent Aleutian Low during winter 1976-77, which constitutes a substantial part of the triggering mechanism of the regime shift. Subsequent sudden changes in the net heat flux occurred in the western North Pacific, particularly in the Kuroshio Extension region, which contributed to the maintenance of the new regime.

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Accepted/In Press date: 10 May 2018
e-pub ahead of print date: 25 May 2018
Published date: June 2018

Identifiers

Local EPrints ID: 421337
URI: http://eprints.soton.ac.uk/id/eprint/421337
ISSN: 2169-9275
PURE UUID: 380a1d6b-4971-4a83-aa6a-dfd96c1db25d

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Date deposited: 01 Jun 2018 16:30
Last modified: 07 Oct 2020 06:13

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Author: Aikaterini Giamalaki
Author: Davide Faranda
Author: Simon Josey
Author: Adrian Martin

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