ISIMIP3a atmospheric climate input data

The Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) provides a framework for the collation of a consistent set of climate impact data across sectors and scales. It also provides a unique opportunity for considering interactions between climate change impacts across sectors through consistent scenarios.<br>The ISIMIP3a part of the third simulation round is dedicated to i) impact model evaluation and improvement and ii) detection and attribution of observed impacts according to the framework of IPCC Working Group II AR5 Chapter 18 and AR6 chapter 16. To this end all simulations are driven by observed socio-economic information combined with either observed (factual) climate data or a detrended (counterfactual) version of the observed climate allowing for the generation of a "no climate change" impact baseline.<br>We provide four factual climate input datasets for ISIMIP3a: GSWP3-W5E5, 20CRv3-W5E5, 20CRv3-ERA5, and 20CRv3. All of them have daily temporal and 0.5° spatial resolution. Their temporal coverage varies, with GSWP3-W5E5 and 20CRv3-W5E5 covering 1901-2019, while 20CRv3-ERA5 and 20CRv3 cover 1901-2021 and 1901-2015, respectively. For every factual dataset (obsclim) we provide an associated counterfactual dataset (counterclim) covering the same time period, 100 years worth of climate data to be used for model spin-up (spinclim), and 50 years worth of climate data for the transition from spinclim to counterclim or obsclim (transclim).