Updating the radiation infrastructure in MESSy (based on MESSy version 2.55)

• Published in: Geoscientific Model Development 2024-08, Vol.17 (15), p.5821-5849
• Main Authors: Nützel, Matthias, Stecher, Laura, Jöckel, Patrick, Winterstein, Franziska, Dameris, Martin, Ponater, Michael, Graf, Phoebe, Kunze, Markus
• Format: Article
• Language: English
• Subjects: Aerosol optical properties; Aerosols; Air pollution; Albedo; Albedo (solar); Analysis; Atmosphere; Atmospheric chemistry; Circulation types; Coding standards; General circulation models; Greenhouse gases; Infrastructure; Infrastructure (Economics); Interfaces; Long wave radiation; Lower stratosphere; Medium-range forecasting; Modular systems; Optical properties; Parameters; Polar vortex; Radiation; Radiative forcing; Radiative transfer; Short wave radiation; Simulation; Software; Stratosphere; Stratosphere radiation; Troposphere; Upper troposphere; Weather forecasting
• ISSN: 1991-9603; 1991-959X; 1991-962X; 1991-9603; 1991-962X
• DOI: 10.5194/gmd-17-5821-2024

The calculation of the radiative transfer is a key component of global circulation models. In this article, we describe the most recent updates of the radiation infrastructure in the Modular Earth Submodel System (MESSy). These updates include the implementation of the PSrad radiation scheme within the RAD submodel. Furthermore, the radiation-related submodels CLOUDOPT (for the calculation of cloud optical properties) and AEROPT (for the calculation of aerosol optical properties) have been updated and are now more flexible in order to deal with different sets of shortwave and longwave bands of radiation schemes. In the wake of these updates, a new submodel (ALBEDO), which features solar-zenith-angle-dependent albedos and a new satellite-based background (white sky) albedo, was created. All of these developments are backward compatible, and previous features of the MESSy radiation infrastructure remain available. Moreover, these developments mark an important step in the use of the ECHAM/MESSy Atmospheric Chemistry (EMAC) model, as the update of the radiation scheme was a key aspect in the development of the sixth generation of the European Centre for Medium-Range Weather Forecasts - HAMburg (ECHAM6) model from ECHAM5. The developments presented here are also aimed towards using the MESSy infrastructure with the ICOsahedral Non-hydrostatic (ICON) model as a base model. The improved infrastructure will also aid in the implementation of additional radiation schemes once this should be needed.