Convergent Response in Aquaplanet Climate Change Experiments with Increasing Horizontal Resolution

General Circulation Models (GCMs) are widely used to understand our climate and to simulate and predict the effects of global warming. They have shown persistent biases in the large-scale features of the general circulation and basic climate statistics, which are attributed mainly to parameterizations, especially the convection parameterization. To address this, Global storm-resolving models (GSRMs) provide an alternative approach to parameterization by explicitly resolving convection and its interaction with other processes through the refinement of the horizontal gridIn a prior study, we showed the physical convergence of the tropical and general circulation structure at a horizontal grid spacing of 2.5 km using aquaplanets. However, questions linger: Does the response to climate warming converge in a simplified framework as aquaplanets? 

 

We will present the effect of increasing horizontal grid spacing on the convergence of the climate change response in aquaplanet experiments. We will focus on the convergence of the storm tracks and jet stream in terms of their location and intensity using the global storm-resolving model ICON. Control runs, and idealized climate change experiments (increasing sea-surface temperature by 4 Kelvin) were conducted at horizontal grid spacing from 160 km to 2.5 km using an aqua-planet configuration. We adopt an aquaplanet configuration to focus on atmospheric phenomena, specifically convection and cloud feedback while reducing the effect of complex interaction with land, topography, sea ice, and seasons. We will discuss the convergence rate of the large-scale circulation, the eddy-driven jet, the subtropical jet, and the storm track and their response to climate warming, characterized by the location, width, and intensity.