Sensitivity of European blocking to physical parameters in a large ensemble climate model experiment

Abstract The occurrence of blocking weather patterns over Europe is analysed in a large ensemble of simulations of a climate model with perturbed physical parameters. The experiments were performed with HadGEM3‐GC3 for the UK Climate Change Projections, and comprise a set of 15 coupled simulations s...

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Main Authors: Tim Woollings, Marie Drouard, David M. H. Sexton, Carol F. McSweeney
Format: Article
Language:English
Published: Wiley 2025-03-01
Series:Atmospheric Science Letters
Subjects:
Online Access:https://doi.org/10.1002/asl.1295
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author Tim Woollings
Marie Drouard
David M. H. Sexton
Carol F. McSweeney
author_facet Tim Woollings
Marie Drouard
David M. H. Sexton
Carol F. McSweeney
author_sort Tim Woollings
collection DOAJ
description Abstract The occurrence of blocking weather patterns over Europe is analysed in a large ensemble of simulations of a climate model with perturbed physical parameters. The experiments were performed with HadGEM3‐GC3 for the UK Climate Change Projections, and comprise a set of 15 coupled simulations supported by a larger suite of 505 atmosphere‐only simulations. Despite the systematic perturbation of 47 different physical constants in the atmosphere‐only experiments, only three were found to have any impact on European blocking frequencies. These reveal the sensitivity of European blocking to orographic drag in winter and to convective entrainment in summer. However, these sensitivities cannot be traced through to the coupled simulations, due to the smaller and more realistic range of perturbations used and likely also to coupled dynamical effects. Overall, we find that although physical sensitivity to the parameterisations exists, adjustment of the parameters is no replacement for further structural improvement in the representation of these processes in the model.
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series Atmospheric Science Letters
spelling doaj-art-d33099b1f23845f495ed61e5c5fd35b82025-08-20T02:40:40ZengWileyAtmospheric Science Letters1530-261X2025-03-01263n/an/a10.1002/asl.1295Sensitivity of European blocking to physical parameters in a large ensemble climate model experimentTim Woollings0Marie Drouard1David M. H. Sexton2Carol F. McSweeney3Atmospheric, Oceanic and Planetary Physics University of Oxford Oxford UKAtmospheric, Oceanic and Planetary Physics University of Oxford Oxford UKMet Office Hadley Centre Exeter UKMet Office Hadley Centre Exeter UKAbstract The occurrence of blocking weather patterns over Europe is analysed in a large ensemble of simulations of a climate model with perturbed physical parameters. The experiments were performed with HadGEM3‐GC3 for the UK Climate Change Projections, and comprise a set of 15 coupled simulations supported by a larger suite of 505 atmosphere‐only simulations. Despite the systematic perturbation of 47 different physical constants in the atmosphere‐only experiments, only three were found to have any impact on European blocking frequencies. These reveal the sensitivity of European blocking to orographic drag in winter and to convective entrainment in summer. However, these sensitivities cannot be traced through to the coupled simulations, due to the smaller and more realistic range of perturbations used and likely also to coupled dynamical effects. Overall, we find that although physical sensitivity to the parameterisations exists, adjustment of the parameters is no replacement for further structural improvement in the representation of these processes in the model.https://doi.org/10.1002/asl.1295atmospheric blockingconvectiondragperturbed physics ensemble
spellingShingle Tim Woollings
Marie Drouard
David M. H. Sexton
Carol F. McSweeney
Sensitivity of European blocking to physical parameters in a large ensemble climate model experiment
Atmospheric Science Letters
atmospheric blocking
convection
drag
perturbed physics ensemble
title Sensitivity of European blocking to physical parameters in a large ensemble climate model experiment
title_full Sensitivity of European blocking to physical parameters in a large ensemble climate model experiment
title_fullStr Sensitivity of European blocking to physical parameters in a large ensemble climate model experiment
title_full_unstemmed Sensitivity of European blocking to physical parameters in a large ensemble climate model experiment
title_short Sensitivity of European blocking to physical parameters in a large ensemble climate model experiment
title_sort sensitivity of european blocking to physical parameters in a large ensemble climate model experiment
topic atmospheric blocking
convection
drag
perturbed physics ensemble
url https://doi.org/10.1002/asl.1295
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AT mariedrouard sensitivityofeuropeanblockingtophysicalparametersinalargeensembleclimatemodelexperiment
AT davidmhsexton sensitivityofeuropeanblockingtophysicalparametersinalargeensembleclimatemodelexperiment
AT carolfmcsweeney sensitivityofeuropeanblockingtophysicalparametersinalargeensembleclimatemodelexperiment