This manuscript compares vertical profiles of black carbon (BC) mixing ratios from two global models (HadGEM3-UKCA and ECHAM5-HAM2) with aircraft observations. The models are found to over-estimate black carbon mixing ratios, particularly in the upper troposphere and tropics. Results of two additional sensitivity tests related to biomass burning emissions and convective wet scavenging are prese...

In global models of the atmosphere convection is parameterised, since the typical scale of this process is smaller than the model resolution. Here we address some of the uncertainties arising from the selection of different algorithms to simulate this process. Four different parameterisations for atmospheric convection, all used in state-of-the-art models, are implemented in the model system EC...

Increased Cloud Condensation Nuclei (CCN) load due to anthropogenic activity might lead to non-precipitating clouds because the cloud drops become smaller (for a constant liquid water content) and, therefore, less efficient in rain formation (aerosol indirect effect). Adding giant CCN (GCCN) into such a cloud can initiate precipitation (namely, 5 drizzle) and, therefore, might counteract the ae...

The authors analyze the performance of 22 Intergovernmental Panel on Climate Change (IPCC) global climate models (GCMs) over all of North America and its western subregion using several different evaluation metrics. They assess the model skill in simulating climatologies of several climate variables and the skill in simulating the daily synoptic patterns. The evaluation is performed by comparin...

Aerosol activation and cloud processing in the global aerosol-climate model ECHAM5-HAM G. J. Roelofs, P. Stier, J. Feichter, E. Vignati, and J. Wilson Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University, Utrecht, The Netherlands Max Planck Institute for Meteorology, The Atmosphere in the Earth System, Hamburg, Germany Institute for the Environment and Sustainability...