In a quest to represent the Earth system, climate models have become more and more complex. This generates problems, for example, hindering model interpretability. This study contributes to a regain of model understanding and proposes simplifications to decrease scheme complexity. We reflect on the reasons for model complexity and the problems it generates or deepens, connecting perspectives from atmospheric science and the philosophy of climate science. Using an emulated perturbed parameter ensemble of the cloud microphysics (CMP) process efficiencies, we investigate the sensitivity of the model to process perturbations. The sensitivity analysis characterizes the scheme and model behavior, contrasting it to physical process understanding as well as an alternative CMP formulation (comparing the 2M (Lohmann et al., 2007, https://doi.org/10.5194/acp-7-3425-2007) to the P3 scheme (Morrison & Milbrandt, 2015, https://doi.org/10.1175/JAS-D-14-0065.1; Dietlicher et al., 2018, https://doi.org/10.5194/gmd-11-1557-2018)). For the 2M scheme, ice crystal autoconversion...

Addressing Complexity in Global Aerosol Climate Model Cloud Microphysics

10.1029/2022MS003571