The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model
Assessments of the impacts of uncertainties in parameters on mean climate and climate change in complex climate models have, to date, largely focussed on perturbations to parameters in the atmosphere component of the model. Here we expand on a previously published study which found the global impact...
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ftucl:oai:eprints.ucl.ac.uk.OAI2:1324184 2023-05-15T14:00:03+02:00 The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model Brierley, CM Collins, M Thorpe, AJ 2010-02 http://discovery.ucl.ac.uk/1324184/ unknown SPRINGER CLIM DYNAM , 34 (2-3) 325 - 343. (2010) Climate Ocean Parameter Uncertainty Ensemble prediction ANTARCTIC CIRCUMPOLAR CURRENT PERTURBED PHYSICS ENSEMBLES GENERAL-CIRCULATION MODELS SURFACE AIR-TEMPERATURE THERMOHALINE CIRCULATION DIAPYCNAL DIFFUSIVITY FLUX ADJUSTMENTS HEAT TRANSPORTS SEA-ICE SENSITIVITY Article 2010 ftucl 2013-11-10T04:51:18Z Assessments of the impacts of uncertainties in parameters on mean climate and climate change in complex climate models have, to date, largely focussed on perturbations to parameters in the atmosphere component of the model. Here we expand on a previously published study which found the global impacts of perturbed ocean parameters on the rate of transient climate change to be small compared to perturbed atmosphere parameters. By separating the climate-change-induced ocean vertical heat transport in each perturbed member into components associated with the resolved flow and each parameterisation scheme, we show that variations in global mean heat uptake in different perturbed versions are an order of magnitude smaller than the average heat uptake. The lack of impact of the perturbations is attributed to (1) the relatively small impact of the perturbation on the direct vertical heat transport associated with the perturbed process and (2) a compensation between those direct changes and indirect changes in heat transport from other processes. Interactions between processes and changes appear to combine in complex ways to limit ensemble spread and uncertainty in the rate of warming. We also investigate regional impacts of the perturbations that may be important for climate change predictions. We find variations across the ensemble that are significant when measured against natural variability. In terms of the experimental set-up used here (models without flux adjustments) we conclude that perturbed physics ensembles with ocean parameter perturbations are an important component of any probabilistic estimate of future climate change, despite the low spread in global mean quantities. Hence, careful consideration should be given to assessing uncertainty in ocean processes in future probabilistic assessments of regional climate change. Article in Journal/Newspaper Antarc* Antarctic Sea ice University College London: UCL Discovery Antarctic |
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Open Polar |
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University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
unknown |
topic |
Climate Ocean Parameter Uncertainty Ensemble prediction ANTARCTIC CIRCUMPOLAR CURRENT PERTURBED PHYSICS ENSEMBLES GENERAL-CIRCULATION MODELS SURFACE AIR-TEMPERATURE THERMOHALINE CIRCULATION DIAPYCNAL DIFFUSIVITY FLUX ADJUSTMENTS HEAT TRANSPORTS SEA-ICE SENSITIVITY |
spellingShingle |
Climate Ocean Parameter Uncertainty Ensemble prediction ANTARCTIC CIRCUMPOLAR CURRENT PERTURBED PHYSICS ENSEMBLES GENERAL-CIRCULATION MODELS SURFACE AIR-TEMPERATURE THERMOHALINE CIRCULATION DIAPYCNAL DIFFUSIVITY FLUX ADJUSTMENTS HEAT TRANSPORTS SEA-ICE SENSITIVITY Brierley, CM Collins, M Thorpe, AJ The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model |
topic_facet |
Climate Ocean Parameter Uncertainty Ensemble prediction ANTARCTIC CIRCUMPOLAR CURRENT PERTURBED PHYSICS ENSEMBLES GENERAL-CIRCULATION MODELS SURFACE AIR-TEMPERATURE THERMOHALINE CIRCULATION DIAPYCNAL DIFFUSIVITY FLUX ADJUSTMENTS HEAT TRANSPORTS SEA-ICE SENSITIVITY |
description |
Assessments of the impacts of uncertainties in parameters on mean climate and climate change in complex climate models have, to date, largely focussed on perturbations to parameters in the atmosphere component of the model. Here we expand on a previously published study which found the global impacts of perturbed ocean parameters on the rate of transient climate change to be small compared to perturbed atmosphere parameters. By separating the climate-change-induced ocean vertical heat transport in each perturbed member into components associated with the resolved flow and each parameterisation scheme, we show that variations in global mean heat uptake in different perturbed versions are an order of magnitude smaller than the average heat uptake. The lack of impact of the perturbations is attributed to (1) the relatively small impact of the perturbation on the direct vertical heat transport associated with the perturbed process and (2) a compensation between those direct changes and indirect changes in heat transport from other processes. Interactions between processes and changes appear to combine in complex ways to limit ensemble spread and uncertainty in the rate of warming. We also investigate regional impacts of the perturbations that may be important for climate change predictions. We find variations across the ensemble that are significant when measured against natural variability. In terms of the experimental set-up used here (models without flux adjustments) we conclude that perturbed physics ensembles with ocean parameter perturbations are an important component of any probabilistic estimate of future climate change, despite the low spread in global mean quantities. Hence, careful consideration should be given to assessing uncertainty in ocean processes in future probabilistic assessments of regional climate change. |
format |
Article in Journal/Newspaper |
author |
Brierley, CM Collins, M Thorpe, AJ |
author_facet |
Brierley, CM Collins, M Thorpe, AJ |
author_sort |
Brierley, CM |
title |
The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model |
title_short |
The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model |
title_full |
The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model |
title_fullStr |
The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model |
title_full_unstemmed |
The impact of perturbations to ocean-model parameters on climate and climate change in a coupled model |
title_sort |
impact of perturbations to ocean-model parameters on climate and climate change in a coupled model |
publisher |
SPRINGER |
publishDate |
2010 |
url |
http://discovery.ucl.ac.uk/1324184/ |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Sea ice |
genre_facet |
Antarc* Antarctic Sea ice |
op_source |
CLIM DYNAM , 34 (2-3) 325 - 343. (2010) |
_version_ |
1766269027295952896 |