For this SI we welcome manuscripts on activities such as MIIPs – Model Intercomparison and Improvement Projects that target long-standing issues in the representation of small-scale processes in numerical weather prediction and climate models. The initiatives may have been taken during the 10-year Polar Prediction Project (PPP) that finished at the end of 2022 or during the Polar Coupled Analysis and Prediction for Services (PCAPS) both part of the WMO World Weather Research Program. These programs suggest an emphasis on processes that are especially important for the polar regions, but contributions that are relevant and important for model performance in other regions of the world are also welcome. Specific targets are the representation of stably stratified boundary layers, mixed-phase clouds and atmospheric coupling with snow and or ice-covered surfaces, sea-ice, ocean mixing etc.
The intention of this SI is to publish results from MIIPs that establish new and improved workflows to facilitate a more efficient path to improved process representation. This includes research-grade observations that are packaged in an easy-to-use format which combine high-frequency observations of the surface and the atmosphere above to be able to directly compare with the parameterizations used in models using time-step data. The Merged Data File (MDF) format that is defined for both observations and model output come with a series of tools that is transferable between models and observational data collections for both file production and analysis. The SI especially welcome contributions that build on, or further develop the MDF concept including new variables, types of data, sites or new analysis tools such as process-oriented diagnostics or insights in models using the targeted files.
Review process: all papers of this special issue underwent the regular interactive peer-review process of Geoscientific Model Development handled by members of the GMD editorial board.