CR 46:197-209 (2011)  -  DOI:

Ability of RCM/GCM couples to represent the relationship of large scale circulation to climate extremes over the Mediterranean region

Helena A. Flocas1,*, Maria Hatzaki1,3, Konstantia Tolika2, Christina Anagnostopoulou2, Effie Kostopoulou3, Christos Giannakopoulos3, Eleni Kolokytha1, Ioannis Tegoulias2

1Department of Environmental Physics and Meteorology, Faculty of Physics, University of Athens, Build. Phys. V, 15784 Athens, Greece
2Department of Meteorology-Climatology, School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
3Institute for Environmental Research and Sustainable Development, National Observatory of Athens, I. Metaxa & V. Pavlou Street, 15236 Athens, Greece

ABSTRACT: The objective of this study was to explore the ability of 3 regional climate models (RCMs), CNRM-Aladin, C4I-RCA3 and KNMI-RACMO along with their parental global climate models (GCMs), ARPEGE and ECHAM5, to represent the relationship between large-scale atmospheric circulation and climate extremes in the Mediterranean region. Subsequently, an evaluation and inter-comparison of these 3 RCM/GCM couples for the present climate was performed. For this purpose, the Regularised Canonical Correlation Analysis (RCCA) was employed and 4 extreme climate indices of temperature and precipitation were used to define extreme events over the study region. The evaluation of these relationships was carried out against gridded observational and reanalysis datasets. It was found that the observed upper air large scale patterns related to climate extremes in the Mediterranean are not very well reproduced by the RCM/GCM couples in all seasons. In addition, in many cases, the coupled models display patterns of extreme climate indices which are not consistent with the accompanied upper level circulation. Furthermore, all coupled models display substantial deficiencies in simulating precipitation extremes. In the case of summer data, the ability of all 3 models is limited, possibly because the strength of the large-scale atmospheric flow decreases, the control exerted by the lateral boundary conditions is weaker, and the nested models are mainly governed by local processes.

KEY WORDS: Large scale circulation · Extreme climate indices · ENSEMBLES · Circulation patterns · RCCA · Regional climate models · Global climate models

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Cite this article as: Flocas HA, Hatzaki M, Tolika K, Anagnostopoulou C and others (2011) Ability of RCM/GCM couples to represent the relationship of large scale circulation to climate extremes over the Mediterranean region. Clim Res 46:197-209.

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