Observation-based temperature and freshwater noise over the Atlantic Ocean

<p>The ocean is forced at the surface by a heat flux and freshwater flux field from the atmosphere. Short-timescale variability in these fluxes, i.e., noise, can influence long-term ocean variability and might even affect the Atlantic meridional overturning circulation (AMOC). Often this noi...

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Main Authors: A. A. Boot, H. A. Dijkstra
Format: Article
Language:English
Published: Copernicus Publications 2025-01-01
Series:Earth System Dynamics
Online Access:https://esd.copernicus.org/articles/16/115/2025/esd-16-115-2025.pdf
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author A. A. Boot
H. A. Dijkstra
H. A. Dijkstra
author_facet A. A. Boot
H. A. Dijkstra
H. A. Dijkstra
author_sort A. A. Boot
collection DOAJ
description <p>The ocean is forced at the surface by a heat flux and freshwater flux field from the atmosphere. Short-timescale variability in these fluxes, i.e., noise, can influence long-term ocean variability and might even affect the Atlantic meridional overturning circulation (AMOC). Often this noise is assumed to be Gaussian, but detailed analyses of its statistics appear to be lacking. Here we study the noise characteristics in reanalysis data for two fields that are commonly used to force ocean-only models: evaporation minus precipitation and 2 m air temperature. We construct several noise models for both fields, and a pointwise normal inverse Gaussian distribution model gives the best performance. An analysis of CMIP6 models shows that these models do a reasonable job at representing the standard deviation and skewness of the noise, but the excess kurtosis is more difficult to capture. The pointwise noise model performs better than the CMIP6 models and can be used as forcing in ocean-only models to study, for example, noise-induced transitions of the AMOC.</p>
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spelling doaj-art-df80f35e277b4dbea507f4fa69a910672025-01-20T08:23:14ZengCopernicus PublicationsEarth System Dynamics2190-49792190-49872025-01-011611515010.5194/esd-16-115-2025Observation-based temperature and freshwater noise over the Atlantic OceanA. A. Boot0H. A. Dijkstra1H. A. Dijkstra2Institute for Marine and Atmospheric research Utrecht, Department of Physics, Utrecht University, Utrecht, the NetherlandsInstitute for Marine and Atmospheric research Utrecht, Department of Physics, Utrecht University, Utrecht, the NetherlandsCenter for Complex Systems Studies, Utrecht University, Utrecht, the Netherlands<p>The ocean is forced at the surface by a heat flux and freshwater flux field from the atmosphere. Short-timescale variability in these fluxes, i.e., noise, can influence long-term ocean variability and might even affect the Atlantic meridional overturning circulation (AMOC). Often this noise is assumed to be Gaussian, but detailed analyses of its statistics appear to be lacking. Here we study the noise characteristics in reanalysis data for two fields that are commonly used to force ocean-only models: evaporation minus precipitation and 2 m air temperature. We construct several noise models for both fields, and a pointwise normal inverse Gaussian distribution model gives the best performance. An analysis of CMIP6 models shows that these models do a reasonable job at representing the standard deviation and skewness of the noise, but the excess kurtosis is more difficult to capture. The pointwise noise model performs better than the CMIP6 models and can be used as forcing in ocean-only models to study, for example, noise-induced transitions of the AMOC.</p>https://esd.copernicus.org/articles/16/115/2025/esd-16-115-2025.pdf
spellingShingle A. A. Boot
H. A. Dijkstra
H. A. Dijkstra
Observation-based temperature and freshwater noise over the Atlantic Ocean
Earth System Dynamics
title Observation-based temperature and freshwater noise over the Atlantic Ocean
title_full Observation-based temperature and freshwater noise over the Atlantic Ocean
title_fullStr Observation-based temperature and freshwater noise over the Atlantic Ocean
title_full_unstemmed Observation-based temperature and freshwater noise over the Atlantic Ocean
title_short Observation-based temperature and freshwater noise over the Atlantic Ocean
title_sort observation based temperature and freshwater noise over the atlantic ocean
url https://esd.copernicus.org/articles/16/115/2025/esd-16-115-2025.pdf
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