The CORDEX.be initiative as a foundation of climate services in Belgium

CORDEX.be is an initiative to gather the Belgian climate and impact modeling research into a network as the first
steps towards the realization of a climate center.
The climate network structure is naturally imposed by the top-down data flow, from the four participating upper-
air Regional Climate Modeling groups towards seven Local Impact Models (LIMs). However, the CORDEX.be
framework and guidelines are designed based on a user-oriented bottom-up approach. The proposed coordination
framework could serve as a demonstration case for regions or countries where the climate-research capacity is present
but a structure is required to assemble it coherently.
The first aim is to contribute to the international climate community by a participation in the EURO-CORDEX
project, that is, the production of regional climate projections. Second, since the “.be” stands both for beyond and
Belgium, an ensemble of High-Resolution (H-Res) results over Belgium will be provided, at convection-permitting
resolutions of ±4 km following uniform prescriptions. Third, these results will be coupled to seven local-impact mod-
els the output of which will be translated to severity indices for extreme events. All results will then be gathered in a
coherent fashion incorporating calibration and statistical downscaling for uncertainty estimation. Lastly, climate ser-
vices provide information about climate and its change, and allow the tailoring of mitigation and adaptation strategies
for specific users. Following interactions with stakeholders different applications are planned, demonstrating the use
of the climate data.
The methodology is based on two cornerstones: the downscaling and the multi-model approaches. Dynamical
downscaling implies that low-resolution large-area model runs are required to force H-Res small-area model runs.
Such dependency therefore naturally determines the timing, the network structure and data exchange within the ini-
tiative. Also the downscaling approach, which is by nature a top-down approach, is combined with a user-oriented
bottom-up approach since local impact models require very specific input of data that must be stored. Akin to interna-
tional frameworks such as CMIP and CORDEX a multi-model approach is taken that allows uncertainty estimation,
a crucial aspect of climate projections for policy-making purposes. However, due to the lack of H-Res model runs,
a combination of all available climate information, both nationally and internationally must be supplemented with
statistical downscaling approaches.
The CORDEX.be framework provides the first building blocks for a research network which could be easily
extended, both nationally and internationally, with the intention of providing climate services.