Status and directions for the CORDEX Initiative.

The COordinated Regional climate Downscaling EXperiment (CORDEX) is backed by the World Climate Research Programme (WCRP). The goal of the initiative is to provide regionally downscaled climate projections for most land regions of the globe, as a compliment to the global climate model projections performed within the fifth Coupled Model Intercomparison Project (CMIP5). It is anticipated that the CORDEX dataset will provide a link to the impacts and adaptation community through its finer resolution than global climate models (GCMs) and regional focus. Participation in CORDEX is open and any researchers performing climate downscaling are encouraged to engage with the initiative. The model evaluation framework consists of dynamical and statistical downscaling performed using the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim re-analysis as “perfect boundary conditions”. The climate projection framework within CORDEX is based on CMIP5. CORDEX focuses on the GCM experiments using emission scenarios known as RCP4.5 and RCP8.5 which represent a moderate and a high-level emission pathways. Progress towards an adequate regional ensemble varies between regions, with simulations for Africa (the original focus) and Europe the most advanced. A number of groups have performed simulations for the CORDEX-AustralAsia domain. While these groups continue to perform and evaluate their simulations, the next step is to make the data available through the Earth System Grid Federation Node at the National Computational Facility in Canberra which will be done through 2015. The next phase of CORDEX is currently being planned and will include a similar downscaling experiment for CMIP6 GCMs, as well as a focus around five key regional challenges: Added value, Human elements, Coordination of Regional Coupled Modelling, Precipitation and Local Wind systems. In addition to the key challenges, four cross-cutting themes have been identified: Water resources and Hydrological cycle, Development of process based metrics, the Water-Energy Nexus and Extremes. Flagship Pilot Studies are one proposed mechanism through which CORDEX will attempt to address these issues.