Journal cover Journal topic
Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
doi:10.5194/gmd-2016-221
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Development and technical paper
25 Oct 2016
Review status
This discussion paper is under review for the journal Geoscientific Model Development (GMD).
Climate pattern scaling set for an ensemble of 22 GCMs – adding uncertainty to the IMOGEN impacts system
Przemyslaw Zelazowski1,2, Chris Huntingford3, Lina M. Mercado4,3, and Nathalie Schaller1,5 1Oxford University Centre for the Environment, University of Oxford, Oxford, OX1 3QY, UK
2Centre of New Technologies, University of Warsaw, Warsaw, 02-097, Poland
3Centre for Ecology and Hydrology, Wallingford, OX10 8BB, UK
4Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
5Center for International Climate and Environmental Research (CICERO), Oslo, NO-0318, Norway
Abstract. Global Circulation Models (GCMs) are the best tool to understand climate change, as they attempt to represent all the important Earth system processes, and including anthropogenic perturbation through fossil fuel burning. However, GCMs are computationally very expensive, which limits the number of simulations that can be made. Pattern-scaling is an emulation technique that takes advantage of the fact that local and seasonal changes in surface climate are often approximately linear in amount of warming over land and globe. This allows interpolation away from a limited number of available GCM simulations, to assess alternative future emissions scenarios. In this paper we present a pattern-scaling set consisting of spatial climate change patterns along with parameters for an energy balance model that calculates the amount of global warming. The set is derived from 22 GCMs of the WCRP CMIP3 database, setting the basis for similar eventual pattern development for CMIP5 ensemble. Critically it extends the use of the IMOGEN (Integrated Model Of Global Effects of climatic aNomalies) framework to enable scanning across full uncertainty in GCMs for impacts studies. Across models, the presented climate patterns represent consistent global mean trends, with maximum four GCMs exhibiting opposite sign of the trend per variable (relative humidity). The described new climate regimes are generally warmer, wetter (but with less snowfall), cloudier and windier, and with decreased relative humidity. Overall, the patterns of the analysed variables explain one-third of regional change in decadal averages (mean Percentage Variance Explained, PVE, 34.25 ± 5.21), but signal in some models exhibits much more linearity (e.g. MIROC3.2(hires):41.53) than in others (GISS_ER: 22.67). The two most often considered variables: near-surface temperature and precipitation, have PVE of 85.44 ± 4.37 and 14.98 ± 4.61, respectively. The dataset is available for download and researchers in the areas of ecosystem modelling and climate change impact assessment are already starting to use it. Besides allowing time-efficient assessment for non-standard future scenarios of changed greenhouse gas (GHG) concentrations, it enables understanding of new representations of land surface processes, and including climate-carbon cycle feedbacks. Current and potential future applications of such modelling system are discussed.

Citation: Zelazowski, P., Huntingford, C., Mercado, L. M., and Schaller, N.: Climate pattern scaling set for an ensemble of 22 GCMs – adding uncertainty to the IMOGEN impacts system, Geosci. Model Dev. Discuss., doi:10.5194/gmd-2016-221, in review, 2016.
Przemyslaw Zelazowski et al.
Przemyslaw Zelazowski et al.
Przemyslaw Zelazowski et al.

Viewed

Total article views: 137 (including HTML, PDF, and XML)

HTML PDF XML Total Supplement BibTeX EndNote
103 26 8 137 7 2 9

Views and downloads (calculated since 25 Oct 2016)

Cumulative views and downloads (calculated since 25 Oct 2016)

Viewed (geographical distribution)

Total article views: 137 (including HTML, PDF, and XML)

Thereof 137 with geography defined and 0 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 29 Mar 2017
Publications Copernicus
Download
Short summary
This paper describes the calibration of the IMOGEN (Integrated Model Of Global Effects of climatic aNomalies) impacts modelling system against 22 Global Climate Models (GCMs) in the CMIP3 database.

IMOGEN uses "pattern-scaling" to emulate GCMs, and with such linearity enables projections to be made for alternative future scenarios of atmospheric greenhouse gas concentrations. It is also coupled to the JULES land surface model, to allow impacts assessments.
This paper describes the calibration of the IMOGEN (Integrated Model Of Global Effects of...
Share