CMIP7 Climate Forcings Dataset: Simple plumes for anthropogenic aerosols in HL, M, L, LN, and ML scenarios

This data release SPv2.1 contains the CMIP7 scenarios HL (High-to-Low), M (Medium), ML (Medium-to-Low), L (Low), and LN (Low-to-Negative) for the Simple Plumes (SP) parameterization. The data sets are for 2023 to 2100 inclusive and are harmonized with the historical data set of SPv2.1 (Fiedler and Azoulay, 2025). Gridded emissions of SO₂ and NH₃ of the corresponding ScenarioMIP-CMIP7 scenarios have been used for the temporal scaling for SP with the same method as for the other two scenarios H (High) and VL (Very Low) (Fiedler and Azoulay, 2026). Used CMIP7 emission datasets (Kikstra et al., 2026) were downloaded from ESGF (IIASA-IAMC-ml-1-1-1, IIASA-IAMC-ln-1-1-1, IIASA-IAMC-l-1-1-1, IIASA-IAMC-m-1-1-1, IIASA-IAMC-hl-1-1-1). 

Each of the five netcdf files published here, namely one per scenario, are input files for the SP parameterization code. The SP code reads the input file and constructs the time-variant and wavelength-dependent three dimensional data of the anthropogenic aerosol optical properties and their effects on cloud droplets. Resulting patterns from the scenario datasets in SP are shown for the mid-visible in the enclosed document along with the CMIP7 historical dataset and the H and VL scenarios of SPv2.1. The source code and description of the SP parameterization is published in Stevens et al. (2017). A journal publication with additional detail and documentation of the CMIP7 SPv2.1 forcing data is in preparation.

The data production of SPv2.1 was supported by the CMIP climate forcings task team. We acknowledge the funding from the ECMWF project ForceDestinE (DE_341_IIASA) for the L scenario and from the EU project EXPECT (No.: 101137656 HORIZON-CL5-2023-D1-01) for other scenarios.