The double ITCZ bias in CMIP5 models: interaction between SST, large-scale circulation and precipitation

Verfasser / Beitragende:
[Boutheina Oueslati, Gilles Bellon]
Ort, Verlag, Jahr:
2015
Enthalten in:
Climate Dynamics, 44/3-4(2015-02-01), 585-607
Format:
Artikel (online)
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024 7 0 |a 10.1007/s00382-015-2468-6  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00382-015-2468-6 
245 0 4 |a The double ITCZ bias in CMIP5 models: interaction between SST, large-scale circulation and precipitation  |h [Elektronische Daten]  |c [Boutheina Oueslati, Gilles Bellon] 
520 3 |a The double intertropical convergence zone (ITCZ) bias still affects all the models that participate to CMIP5 (Coupled Model Intercomparison Project, phase 5). As an ensemble, general circulation models have improved little between CMIP3 and CMIP5 as far as the double ITCZ is concerned. The present study proposes a new process-oriented metrics that provides a robust statistical relationship between atmospheric processes and the double ITCZ bias, additionally to the existing relationship between the sea surface temperature (SST) and the double ITCZ bias. The SST contribution is examined using the THR-MLT index (Bellucci et al. in J Clim 5:1127-1145, 2010), which combines biases on the representation of local SSTs and the SST threshold leading to the onset of ascent in the double ITCZ region. As a metrics of a model's bias in simulating the interaction between circulation and precipitation, we propose to use the Combined Precipitation Circulation Error (CPCE). It is computed as the quadratic error on the contribution of each vertical regime to the total precipitation over the tropical oceans. CPCE is a global measure of the circulation-precipitation coupling that characterizes the model physical parameterizations rather than the regional characteristics of the eastern Pacific. A linear regression analysis shows that most of the double ITCZ spread among CMIP5 coupled ocean-atmosphere models is attributed to SST biases, and that the precipitation large-scale dynamics relationship explains a significant fraction of the bias in these models, as well as in the atmosphere-only models. 
540 |a Springer-Verlag Berlin Heidelberg, 2015 
690 7 |a Double ITCZ  |2 nationallicence 
690 7 |a Atmospheric dynamics  |2 nationallicence 
690 7 |a Coupled ocean-atmosphere feedbacks  |2 nationallicence 
700 1 |a Oueslati  |D Boutheina  |u Centre National de Recherches Météorologiques (CNRS)/Météo-France, 42, Avenue Gaspard Coriolis, 31057, Toulouse, France  |4 aut 
700 1 |a Bellon  |D Gilles  |u Centre National de Recherches Météorologiques (CNRS)/Météo-France, 42, Avenue Gaspard Coriolis, 31057, Toulouse, France  |4 aut 
773 0 |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 44/3-4(2015-02-01), 585-607  |x 0930-7575  |q 44:3-4<585  |1 2015  |2 44  |o 382 
856 4 0 |u https://doi.org/10.1007/s00382-015-2468-6  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00382-015-2468-6  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Oueslati  |D Boutheina  |u Centre National de Recherches Météorologiques (CNRS)/Météo-France, 42, Avenue Gaspard Coriolis, 31057, Toulouse, France  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Bellon  |D Gilles  |u Centre National de Recherches Météorologiques (CNRS)/Météo-France, 42, Avenue Gaspard Coriolis, 31057, Toulouse, France  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 44/3-4(2015-02-01), 585-607  |x 0930-7575  |q 44:3-4<585  |1 2015  |2 44  |o 382