The CNRM-CM5.1 global climate model: description and basic evaluation

Abstract

A new version of the general circulation model CNRM-CM has been developed jointly by CNRM-GAME (Centre National de Recherches Météorologiques-Groupe d'études de l'Atmosphère Météorologique) and Cerfacs (Centre Européen de Recherche et de Formation Avancée) in order to contribute to phase 5 of the Coupled Model Intercomparison Project (CMIP5). The purpose of the study is to describe its main features and to provide a preliminary assessment of its mean climatology. CNRM-CM5.1 includes the atmospheric model ARPEGE-Climat (v5.2), the ocean model NEMO (v3.2), the land surface scheme ISBA and the sea ice model GELATO (v5) coupled through the OASIS (v3) system. The main improvements since CMIP3 are the following. Horizontal resolution has been increased both in the atmosphere (from 2.8°to 1.4°) and in the ocean (from 2°t o 1°). The dynamical core of the atmospheric component has been revised. A new radiation scheme has been introduced and the treatments of tropospheric and stratospheric aerosols have been improved. Particular care has been devoted to ensure mass/water conservation in the atmospheric component. The land surface scheme ISBA has been externalised from the atmospheric model through the SURFEX platform and includes new developments such as a parameterization of sub-grid hydrology, a new freezing scheme and a new bulk parameterisation for ocean surface fluxes. The ocean model is based on the state-of-the-art version of NEMO, which has greatly progressed since the OPA8.0 version used in the CMIP3 version of CNRM-CM. Finally, the coupling between the different components through OASIS has also received a particular attention to avoid energy loss and spurious drifts. These developments generally lead to a more realistic representation of the mean recent climate and to a reduction of drifts in a preindustrial integration. The largescale dynamics is generally improved both in the atmosphere and in the ocean, and the bias in mean surface temperature is clearly reduced. However, some flaws remain such as significant precipitation and radiative biases in many regions, or a pronounced drift in three dimensional salinity.

Internal variability in simulated and observed tropical tropospheric temperature trends

“…For simulations, we use historical and RCP4.5 runs from 44 different GCMs from the CMIP5 archive [Taylor et al, 2012;Bi et al, 2013;Xin et al, 2013;Ji et al, 2014;von Salzen et al, 2013;Meehl et al, 2012;Hurrell et al, 2012;Scoccimarro et al, 2011;Voldoire et al, 2013;Rotstayn et al, 2010;Hazeleger et al, 2010;Li et al, 2013;Delworth et al, 2006;Donner et al, 2011;Schmidt et al, 2014;Smith et al, 2010;Collins et al, 2011;Jones et al, 2011;Volodin et al, 2010;Dufresne et al, 2013;Hourdin et al, 2013;Sakamoto et al, 2012;Watanabe et al, 2010Watanabe et al, , 2011Giorgetta et al, 2013;Yukimoto et al, 2012;Bentsen et al, 2013], and from the 100 realization single-model large ensemble of the MPI-ESM [Giorgetta et al, 2013]. The large ensemble uses the model version MPI-ESM1.1 in low resolution (LR) configuration, with resolution T63 and 47 vertical levels in the atmosphere and 1.5 ∘ resolution and 40 vertical levels in the ocean.…”

A fully coupled atmosphere–ocean wave modeling system for the Mediterranean Sea: interactions and sensitivity to the resolved scales and mechanisms

“…The Earth system model (CNRM-CM5, Centre National de Recherches M'etéorologiques Coupled Global Climate Model version 5) running operationally at Meteo-France consists of several existing models designed independently and coupled through the OASIS software (Redler et al, 2010). It includes the ARPEGE (Action de Recherche Petite Echelle Grande Echelle) model for the atmosphere, the NEMO (Nucleus for European Modelling of the Ocean) model for the ocean circulation, the GELATO (Global Experimental Leads and ice for ATmosphere and Ocean) model for sea-ice, the SURFEX (Surface Externalisée) model for land and the ocean-atmospheric fluxes, and the TRIP (total runoff integrating pathways) model to simulate river routing and water discharge from rivers to the ocean (Voldoire et al, 2012).…”

Skill assessment of three earth system models with common marine biogeochemistry

“…The CNRM-CM5.1 model (CNRMCM5, Voldoire et al 2012 this issue) couples atmosphere, land, ocean, and sea-ice components. The atmospheric component is ARPEGE-CLIMATv5.2, which derives from ARPEGE (action de recherche petite echelle grande echelle, which means research project on small and large scales, Déqué et al 1994).…”

“…In ORCA1, a nominal resolution of 1°at the equator is chosen to which a latitudinal grid refinement of 1/3°is added in the tropics. The vertical discretization accounts for 42 levels and also (Hourdin et al 2006) 2°9 2°cos(/) 9 31L (Madec et al 1998) 2°9 2°cos(/) (Fichefet et al 1997) 3.75°9 2.5° ( Krinner et al 2005) IPSLCM5 (Dufresne et al 2012) LMDZ-4 NEMOv3.2 LIM2 ORCHIDEE 3.6°9 1.8°9 39L (Hourdin et al 2006) 2°9 2°cos(/) 9 31L (Madec 2008a, b) 2°9 2°cos(/) (Fichefet et al 1997) 3.6°9 1.8° ( Krinner et al 2005) CNRMCM5 (Voldoire et al 2012) ARPEGE-CLIMATv5.2 NEMOv3.2 GELATO SURFEX T127 * 1.4°9 31L (Voldoire et al 2012) 1°9 1°cos(/) 9 42L (Madec 2008a, b;Hewitt et al 2011) 1°9 1°cos(/) (Salas y Mélia 2002) *1.4° (Noilhan and Mahfouf 1996) Skill assessment of three earth system models 2551 includes partial-steps. Compared to IPSLCM5, this configuration includes an improvement of the Turbulent Kinetic Energy closure scheme (Madec 2008a, b) from Blanke and Delecluse (1993).…”

“…This biogeochemical model further includes a representation of the iron cycle and limitation by multiple nutrients (Aumont 2003;Schneider et al 2008). Additionally, in the three selected Earth System Models, each of the ocean circulation models is based on the same code, although versions differ as to resolution and subgrid-scale physics (Madec 2008a, b;Marti et al 2010;Voldoire et al 2012;Dufresne et al 2012). The largest differences in simulated ocean circulation fields probably stem from each ocean model being coupled to a different atmospheric model.…”