CMIP Climate Forcings Dataset: Simple plumes for anthropogenic aerosols

The Simple Plumes (SP) parameterization (Stevens et al., 2017) mimics the changes of the global patterns for the optical properties and cloud effects of anthropogenic aerosols. The parameterization was originally developed for use in a set of experiments in the CMIP6-endorsed Radiative Forcing Model Intercomparison Project (RFMIP, Pincus et al., 2016) and helped to explain differences in the effective radiative forcing of anthropogenic aerosols (Fiedler et al., 2023). Code of the SP parameterization is available in the supplementary material of Stevens et al. (2017). Since the release of SP,  models implemented the parameterization also for applications other than RFMIP. Users of the parameterization have requested new input data for SP based on CMIP7 emission data in the framework of the CMIP Climate Forcings Task Team. 

We provide here the SP dataset for the time period 1850 to 2020 inclusive (SPv2), based on the preliminary data set of CEDS for CMIP6plus version CMIP_CEDS-2024-10-21. We use the decadal scaling method for gridded SO2 and NH3 emissions (Fiedler et al., 2019) and transfered it to the historical period to update and extent the earlier time series for 1850 to 2014 (Stevens et al., 2017). The here published SPv2 data are currently tested by early adopters for their applications. Results of the evaluation of SPv2 will be published in a scientific journal and linked once they are available.

The SPv2 data is intended for use in CMIP experiments and other applications. Information about all CMIP forcing datasets are available from input4MIPs.