The single-column version of the shared ALADIN-HIRLAM numerical weather prediction system, called MUSC, was developed by Météo-France in the 2000s and has a growing user-base. Tools to derive the required input, to run experiments and to handle outputs have been developed within the HARMONIE-AROME configuration of the ALADIN-HIRLAM system. We also illustrate the usefulness of MUSC for testing and developing physical parametrizations related to cloud microphysics and radiative transfer.

Numerical weather prediction model HIRLAM includes prognostic treatment of lake surface state since 2012. Forecast is based on the Freshwater Lake model (Flake). We compared the predicted lake water temperature, freeze-up and break-up dates as well as the ice thickness and snow depth during six years over 45 lakes in Finland against observations by Finnish Environment Institute. Water surface temperatures and freezing of lakes were well predicted but the ice tended to melt too early in spring.

Global radiation forecasts by HARMONIE-AROME numerical weather prediction model were compared to observations over Finland in spring 2017 when convective clouds, rain and snow showers were frequent. In HARMONIE-AROME, three different schemes for parametrization of the atmospheric radiation transfer are available. Differences between the schemes and observations showed up especially as variations in the hourly scale. The results by the schemes were closer to each other than to the observations.

This paper provides an overview of the HLRADIA shortwave (SW) and longwave (LW) broadband radiation schemes used in the HIRLAM numerical weather prediction (NWP) model and available in the HARMONIE-AROME mesoscale NWP model. The advantage of broadband, over spectral, schemes is that they can be called more frequently within the NWP model, without compromising on computational efficiency. Fast physically based radiation parametrizations are also valuable for high-resolution ensemble forecasting.

The direct shortwave (SW) radiative effect of aerosols under clear-sky conditions in the ALADIN-HIRLAM numerical weather prediction system was investigated using three SW radiation schemes in diagnostic single-column experiments. Each scheme accurately simulates the direct SW effect when observed aerosols are used, particularly for heavy pollution scenarios.