Quantifying the contribution of forcing and three prominent modes of variability to historical climate
Climate models can produce accurate representations of the most important modes of climate variability, but they cannot be expected to follow their observed time evolution. This makes direct comparison of simulated and observed variability difficult and creates uncertainty in estimates of forced cha...
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Language: | English |
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2023
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Online Access: | http://hdl.handle.net/2078.1/274654 https://doi.org/10.5194/cp-19-943-2023 |
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ftunivlouvain:oai:dial.uclouvain.be:boreal:274654 2024-05-12T08:07:52+00:00 Quantifying the contribution of forcing and three prominent modes of variability to historical climate Schurer, Andrew P. Hegherl, Gabriela Goosse, Hugues Bollasina, Massimo England, Matthew Mineter, Mickael Doug, Smith Tett, Simon UCL - SST/ELI/ELIC - Earth & Climate 2023 http://hdl.handle.net/2078.1/274654 https://doi.org/10.5194/cp-19-943-2023 eng eng Copernicus GmbH boreal:274654 http://hdl.handle.net/2078.1/274654 doi:10.5194/cp-19-943-2023 urn:ISSN:1814-9324 urn:EISSN:1814-9332 info:eu-repo/semantics/openAccess Climate of the Past, Vol. 19, no.5, p. 943-957 (2023) info:eu-repo/semantics/article 2023 ftunivlouvain https://doi.org/10.5194/cp-19-943-2023 2024-04-17T16:30:19Z Climate models can produce accurate representations of the most important modes of climate variability, but they cannot be expected to follow their observed time evolution. This makes direct comparison of simulated and observed variability difficult and creates uncertainty in estimates of forced change. We investigate the role of three modes of climate variability, the North Atlantic Oscillation, El Niño–Southern Oscillation and the Southern Annular Mode, as pacemakers of climate variability since 1781, evaluating where their evolution masks or enhances forced climate trends. We use particle filter data assimilation to constrain the observed variability in a global climate model without nudging, producing a near-free-running model simulation with the time evolution of these modes similar to those observed. Since the climate model also contains external forcings, these simulations, in combination with model experiments with identical forcing but no assimilation, can be used to compare the forced response to the effect of the three modes assimilated and evaluate the extent to which these are confounded with the forced response. The assimilated model is significantly closer than the “forcing only†simulations to annual temperature and precipitation observations over many regions, in particular the tropics, the North Atlantic and Europe. The results indicate where initialised simulations that track these modes could be expected to show additional skill. Assimilating the three modes cannot explain the large discrepancy previously found between observed and modelled variability in the southern extra-tropics but constraining the El Niño–Southern Oscillation reconciles simulated global cooling with that observed after volcanic eruptions. Article in Journal/Newspaper North Atlantic North Atlantic oscillation DIAL@UCLouvain (Université catholique de Louvain) Climate of the Past 19 5 943 957 |
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Open Polar |
collection |
DIAL@UCLouvain (Université catholique de Louvain) |
op_collection_id |
ftunivlouvain |
language |
English |
description |
Climate models can produce accurate representations of the most important modes of climate variability, but they cannot be expected to follow their observed time evolution. This makes direct comparison of simulated and observed variability difficult and creates uncertainty in estimates of forced change. We investigate the role of three modes of climate variability, the North Atlantic Oscillation, El Niño–Southern Oscillation and the Southern Annular Mode, as pacemakers of climate variability since 1781, evaluating where their evolution masks or enhances forced climate trends. We use particle filter data assimilation to constrain the observed variability in a global climate model without nudging, producing a near-free-running model simulation with the time evolution of these modes similar to those observed. Since the climate model also contains external forcings, these simulations, in combination with model experiments with identical forcing but no assimilation, can be used to compare the forced response to the effect of the three modes assimilated and evaluate the extent to which these are confounded with the forced response. The assimilated model is significantly closer than the “forcing only†simulations to annual temperature and precipitation observations over many regions, in particular the tropics, the North Atlantic and Europe. The results indicate where initialised simulations that track these modes could be expected to show additional skill. Assimilating the three modes cannot explain the large discrepancy previously found between observed and modelled variability in the southern extra-tropics but constraining the El Niño–Southern Oscillation reconciles simulated global cooling with that observed after volcanic eruptions. |
author2 |
UCL - SST/ELI/ELIC - Earth & Climate |
format |
Article in Journal/Newspaper |
author |
Schurer, Andrew P. Hegherl, Gabriela Goosse, Hugues Bollasina, Massimo England, Matthew Mineter, Mickael Doug, Smith Tett, Simon |
spellingShingle |
Schurer, Andrew P. Hegherl, Gabriela Goosse, Hugues Bollasina, Massimo England, Matthew Mineter, Mickael Doug, Smith Tett, Simon Quantifying the contribution of forcing and three prominent modes of variability to historical climate |
author_facet |
Schurer, Andrew P. Hegherl, Gabriela Goosse, Hugues Bollasina, Massimo England, Matthew Mineter, Mickael Doug, Smith Tett, Simon |
author_sort |
Schurer, Andrew P. |
title |
Quantifying the contribution of forcing and three prominent modes of variability to historical climate |
title_short |
Quantifying the contribution of forcing and three prominent modes of variability to historical climate |
title_full |
Quantifying the contribution of forcing and three prominent modes of variability to historical climate |
title_fullStr |
Quantifying the contribution of forcing and three prominent modes of variability to historical climate |
title_full_unstemmed |
Quantifying the contribution of forcing and three prominent modes of variability to historical climate |
title_sort |
quantifying the contribution of forcing and three prominent modes of variability to historical climate |
publisher |
Copernicus GmbH |
publishDate |
2023 |
url |
http://hdl.handle.net/2078.1/274654 https://doi.org/10.5194/cp-19-943-2023 |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
Climate of the Past, Vol. 19, no.5, p. 943-957 (2023) |
op_relation |
boreal:274654 http://hdl.handle.net/2078.1/274654 doi:10.5194/cp-19-943-2023 urn:ISSN:1814-9324 urn:EISSN:1814-9332 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/cp-19-943-2023 |
container_title |
Climate of the Past |
container_volume |
19 |
container_issue |
5 |
container_start_page |
943 |
op_container_end_page |
957 |
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1798850668456312832 |