Combining global climate models using graph cuts
Details
Serval ID
serval:BIB_69639A9842C6
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Combining global climate models using graph cuts
Journal
Climate Dynamics
ISSN
0930-7575
1432-0894
1432-0894
Publication state
Published
Issued date
15/03/2022
Peer-reviewed
Oui
Language
english
Abstract
Global Climate Models are the main tools for climate projections. Since many models exist, it is common to use Multi-Model Ensembles to reduce biases and assess uncertainties in climate projections. Several approaches have been proposed to combine individual models and extract a robust signal from an ensemble. Among them, the Multi-Model Mean (MMM) is the most commonly used. Based on the assumption that the models are centered around the truth, it consists in averaging the ensemble, with the possibility of using equal weights for all models or to adjust weights to favor some models. In this paper, we propose a new alternative to reconstruct multi-decadal means of climate variables from a Multi-Model Ensemble, where the local performance of the models is taken into account. This is in contrast with MMM where a model has the same weight for all locations. Our approach is based on a computer vision method called graph cuts and consists in selecting for each grid point the most appropriate model, while at the same time considering the overall spatial consistency of the resulting field. The performance of the graph cuts approach is assessed based on two experiments: one where the ERA5 reanalyses are considered as the reference, and another involving a perfect model experiment where each model is in turn considered as the reference. We show that the graph cuts approach generally results in lower biases than other model combination approaches such as MMM, while at the same time preserving a similar level of spatial continuity.
Keywords
Atmospheric Science
Web of science
Open Access
Yes
Funding(s)
European Research Council (ERC) / 565338965-A2C2
University of Lausanne
Create date
08/04/2022 13:42
Last modification date
19/08/2022 6:10