The OASIS3 coupler: a European climate modelling community software

Abstract. This paper presents the OASIS3 software used in five of the seven European Earth System Models (ESMs) participating to the Fifth Coupled Model Intercomparison Project (CMIP5). A short history of the coupler development and a description of its large community of users are followed by a detailed OASIS3 technical description. The performances of few relatively high resolution OASIS3 coupled models are then described and show that even if its limited field-per-field parallelism will eventually become a bottleneck in the simulation, OASIS3 can still be considered an appropriate tool for most of these relatively heavy coupled configurations. Its successful use in different CMIP5 ESMs is then detailed. A discussion of the benefits and drawbacks of the OASIS3 approach and a presentation of planned developments conclude the paper.