Beyond ozone hole impacts: Seamless composition-climate interactions explored with ICON-ART

The ICOsahedral Non-hydrostatic (ICON) modelling system was originally developed by DWD and MPI-M for a range of weather (forecast) and climate applications. An Aerosols and Reactive Tracers (ART) module was added by KIT to enable a comprehensive assessment of composition interactions within the atmospheric domain. Recognising that atmospheric processes happen on a multitude of temporal and spatial scales, flexible horizontal and vertical grid options are a key element of versatile model configurations in use. Here, we present a selection of results from different ICON-ART configurations that explore (stratospheric) ozone-climate interactions and stratosphere-troposphere coupling – e.g. regional climatic impacts of the ozone hole (and ozone losses in other regions) and global warming induced changes in jet-streams – in different types of integrations. In addition, we explore the potential to forecast “chemical weather” with ICON-ART, including environmental (UV) indices.

Starting with time-slice experiments, we provide a range of examples using the ICON-ART modelling system to investigate (idealised) climate change scenarios with respect to different threshold temperatures (reached under global warming) and the climatic impact of the ozone hole (and ozone losses in other regions). For the latter, halogen induced depletion of (stratospheric) ozone can be switched on and off in our modelling world. We illustrate how such integrations allow the unambiguous attribution of certain climate change effects, e.g. the contribution of the ozone hole (and other regional ozone losses) to regional surface warming in Antarctica and changes to regional and global “effective radiative forcing”, and the change of jet stream variability under global warming. Moving on, we explore the capability of ICON-ART to work with regionally nested grids to capture accurately smaller spatial scales and to provide “meaningful” forecasts of environmental (UV) indices, thus, demonstrating comprehensively the seamless philosophy regarding processes, scales and applications with the flexible ICON-ART modelling system.