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Detectability of an AMOC decline in current and projected climate changes

Detectability of an AMOC decline in current and projected climate changes
Detectability of an AMOC decline in current and projected climate changes
Determining whether the Atlantic Meridional Overturning Circulation (AMOC)'s transport is in decline is challenging due to the short duration of continuous observations. To estimate how many years are needed to detect a decline, we conduct a simulation study using synthetic data that mimics an AMOC time series. The time series' characteristics are reproduced using the trend, variance, and autocorrelation coefficient of the AMOC strength at 26.5°N from 20 Coupled Model Intercomparison Project Phase 5 (CMIP5) models under the RCP8.5 future scenario, and from RAPID observations (2004–2018). Our results suggest that the 14‐year RAPID length has just entered the lower limits of the trend's “detection window” based on synthetic data generated using CMIP5 trends and variability (14–42 years; median urn:x-wiley:grl:media:grl61393:grl61393-math-0001 24 years), but twice the length is required for detectability based on RAPID variability (29–67 years; median urn:x-wiley:grl:media:grl61393:grl61393-math-0002 43 years). The annual RAPID trend is currently not statistically significant (−0.11 Sv yr−1, p > 0.05).
0094-8276
Lobelle, D.
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Beaulieu, C.
13ae2c11-ebfe-48d9-bda9-122cd013c021
Livina, V.
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Sévellec, F.
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Frajka‐williams, E.
2b2338d1-4a28-4785-9e13-c46c35a326b3
Lobelle, D.
0dccc47f-5187-4b10-a6da-f46d10d1fa3e
Beaulieu, C.
13ae2c11-ebfe-48d9-bda9-122cd013c021
Livina, V.
a4cb0954-12cc-41b5-848e-c01b1578f987
Sévellec, F.
01569d6c-65b0-4270-af2a-35b0a77c9140
Frajka‐williams, E.
2b2338d1-4a28-4785-9e13-c46c35a326b3

Lobelle, D., Beaulieu, C., Livina, V., Sévellec, F. and Frajka‐williams, E. (2020) Detectability of an AMOC decline in current and projected climate changes. Geophysical Research Letters, 47 (20), [e2020GL089974]. (doi:10.1029/2020GL089974).

Record type: Article

Abstract

Determining whether the Atlantic Meridional Overturning Circulation (AMOC)'s transport is in decline is challenging due to the short duration of continuous observations. To estimate how many years are needed to detect a decline, we conduct a simulation study using synthetic data that mimics an AMOC time series. The time series' characteristics are reproduced using the trend, variance, and autocorrelation coefficient of the AMOC strength at 26.5°N from 20 Coupled Model Intercomparison Project Phase 5 (CMIP5) models under the RCP8.5 future scenario, and from RAPID observations (2004–2018). Our results suggest that the 14‐year RAPID length has just entered the lower limits of the trend's “detection window” based on synthetic data generated using CMIP5 trends and variability (14–42 years; median urn:x-wiley:grl:media:grl61393:grl61393-math-0001 24 years), but twice the length is required for detectability based on RAPID variability (29–67 years; median urn:x-wiley:grl:media:grl61393:grl61393-math-0002 43 years). The annual RAPID trend is currently not statistically significant (−0.11 Sv yr−1, p > 0.05).

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2020GL089974 (1) - Version of Record
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Accepted/In Press date: 13 October 2020
Published date: 28 October 2020

Identifiers

Local EPrints ID: 445156
URI: http://eprints.soton.ac.uk/id/eprint/445156
ISSN: 0094-8276
PURE UUID: eceb4f4e-8379-4fc6-8fd1-3b4a6b50130a

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Date deposited: 24 Nov 2020 17:30
Last modified: 25 Nov 2021 20:38

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Contributors

Author: D. Lobelle
Author: C. Beaulieu
Author: V. Livina
Author: F. Sévellec
Author: E. Frajka‐williams

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