Changes in External Forcings Drive Divergent AMOC Responses Across CESM Generations
Abstract It has been suggested that the Atlantic meridional overturning circulation (AMOC) in many CMIP6 models is overly sensitive to anthropogenic aerosol forcing, and it has been proposed that this is due to the inclusion of aerosol indirect effects for the first time in many CMIP6 models. We ana...
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ftdoajarticles:oai:doaj.org/article:a495c650de784eab853356475aae7e65 2024-09-09T19:57:09+00:00 Changes in External Forcings Drive Divergent AMOC Responses Across CESM Generations Michael R. Needham Douglas D. Falter David A. Randall 2024-03-01T00:00:00Z https://doi.org/10.1029/2023GL106410 https://doaj.org/article/a495c650de784eab853356475aae7e65 EN eng Wiley https://doi.org/10.1029/2023GL106410 https://doaj.org/toc/0094-8276 https://doaj.org/toc/1944-8007 1944-8007 0094-8276 doi:10.1029/2023GL106410 https://doaj.org/article/a495c650de784eab853356475aae7e65 Geophysical Research Letters, Vol 51, Iss 5, Pp n/a-n/a (2024) AMOC aerosol‐cloud‐climate interactions CESM large ensembles poleward energy transport Geophysics. Cosmic physics QC801-809 article 2024 ftdoajarticles https://doi.org/10.1029/2023GL106410 2024-08-05T17:49:23Z Abstract It has been suggested that the Atlantic meridional overturning circulation (AMOC) in many CMIP6 models is overly sensitive to anthropogenic aerosol forcing, and it has been proposed that this is due to the inclusion of aerosol indirect effects for the first time in many CMIP6 models. We analyze the AMOC response in a newly released ensemble of simulations performed with CESM2 forced by the CMIP5 input data sets (CESM2‐CMIP5). This AMOC response is then compared to the CMIP5‐generation CESM1 large ensemble (CESM1‐LE) and the CMIP6‐generation CESM2 large ensemble (CESM2‐LE). A key conclusion, only made possible by this experimental setup, is that changes in aerosol‐indirect effects cannot explain differences in AMOC response between CESM1‐LE and CESM2‐LE. Instead, we hypothesize that the difference is due to increased interannual variability of anthropogenic emissions. This forcing variability may act through a nonlinear relationship between the surface heat budget of the North Atlantic and the AMOC. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Geophysical Research Letters 51 5 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
AMOC aerosol‐cloud‐climate interactions CESM large ensembles poleward energy transport Geophysics. Cosmic physics QC801-809 |
spellingShingle |
AMOC aerosol‐cloud‐climate interactions CESM large ensembles poleward energy transport Geophysics. Cosmic physics QC801-809 Michael R. Needham Douglas D. Falter David A. Randall Changes in External Forcings Drive Divergent AMOC Responses Across CESM Generations |
topic_facet |
AMOC aerosol‐cloud‐climate interactions CESM large ensembles poleward energy transport Geophysics. Cosmic physics QC801-809 |
description |
Abstract It has been suggested that the Atlantic meridional overturning circulation (AMOC) in many CMIP6 models is overly sensitive to anthropogenic aerosol forcing, and it has been proposed that this is due to the inclusion of aerosol indirect effects for the first time in many CMIP6 models. We analyze the AMOC response in a newly released ensemble of simulations performed with CESM2 forced by the CMIP5 input data sets (CESM2‐CMIP5). This AMOC response is then compared to the CMIP5‐generation CESM1 large ensemble (CESM1‐LE) and the CMIP6‐generation CESM2 large ensemble (CESM2‐LE). A key conclusion, only made possible by this experimental setup, is that changes in aerosol‐indirect effects cannot explain differences in AMOC response between CESM1‐LE and CESM2‐LE. Instead, we hypothesize that the difference is due to increased interannual variability of anthropogenic emissions. This forcing variability may act through a nonlinear relationship between the surface heat budget of the North Atlantic and the AMOC. |
format |
Article in Journal/Newspaper |
author |
Michael R. Needham Douglas D. Falter David A. Randall |
author_facet |
Michael R. Needham Douglas D. Falter David A. Randall |
author_sort |
Michael R. Needham |
title |
Changes in External Forcings Drive Divergent AMOC Responses Across CESM Generations |
title_short |
Changes in External Forcings Drive Divergent AMOC Responses Across CESM Generations |
title_full |
Changes in External Forcings Drive Divergent AMOC Responses Across CESM Generations |
title_fullStr |
Changes in External Forcings Drive Divergent AMOC Responses Across CESM Generations |
title_full_unstemmed |
Changes in External Forcings Drive Divergent AMOC Responses Across CESM Generations |
title_sort |
changes in external forcings drive divergent amoc responses across cesm generations |
publisher |
Wiley |
publishDate |
2024 |
url |
https://doi.org/10.1029/2023GL106410 https://doaj.org/article/a495c650de784eab853356475aae7e65 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Geophysical Research Letters, Vol 51, Iss 5, Pp n/a-n/a (2024) |
op_relation |
https://doi.org/10.1029/2023GL106410 https://doaj.org/toc/0094-8276 https://doaj.org/toc/1944-8007 1944-8007 0094-8276 doi:10.1029/2023GL106410 https://doaj.org/article/a495c650de784eab853356475aae7e65 |
op_doi |
https://doi.org/10.1029/2023GL106410 |
container_title |
Geophysical Research Letters |
container_volume |
51 |
container_issue |
5 |
_version_ |
1809928043403149312 |