We are happy to announce that the first ISIMIP4a data package is finalized and fully accessible at DKRZ since 13 August. The ISIMIP 4a Fast Track protocol can be found here.
The ISIMIP4a model evaluation experiments are mostly analogous to the ISIMIP3a model evaluation experiments, but the extended (and partly updated) climate-related and direct human forcings now also cover the most recent years up to 2025. In addition to the ‘histsoc’ experiments accounting for historical changes in DHF, the protocol includes a 2021soc experiment where DHF is held constant at 2021 levels; analogous to the 2015soc experiment in ISIMIP3a. This is aligned with the CMIP7 historical period ending in 2021.
We are also about to provide a similar data package for the ISIMIP4b Fast Track including climate simulations from the first CMIP7-ScenarioMIP ESM EC-EARTH! We already have all the required data for the preindustrial, historical and VL and H simulations and now work on the bias-adjustment and the associated DHF for the group I (preindustrial and historical), group II (2021soc future projections), and group III (no adaptation future projections accounting for DHF changing according to SSP storylines but not in response to climate change) experiments. This will come very soon.
