Upscale influences of tropical convection on atmospheric circulation in kilometre-scale climate simulations

Deep moist convection within the Tropics plays an important role in the vertical transport and mixing of energy, heat, and moisture within the atmosphere, leading to notable upscale impacts on broader atmospheric circulation. However, the representation of moist convection and how it influences larger-scale atmospheric dynamics remains a challenge in weather and climate prediction, particularly within global models. The development of large-domain convection-permitting models (CPMs) at the kilometre-scale have transformed the way in which convection and its related processes and scale interactions can be both represented and investigated. Such simulations are now increasingly important for training machine-learning models, as well as for science and direct prediction. The UPSCALE project, funded by the UK Met Office, is evaluating a hierarchy of global and pan-tropical and limited area simulations of the Unified Model, and using this hierarchy to explore convection-driven scale-interactions. Here, we test the hypothesis that an improved representation of organisation of tropical convection in CPMs, primarily through mesoscale convective systems (MCSs) and their associated 'footprints', improves modelled upscale influences of convection on larger-scale atmospheric dynamics, such as those associated with Hadley and Walker circulations. We explore the role of MCSs in atmospheric heating and vertical transport, comparing various dynamical and thermodynamical relationships within large-domain convection-permitting climate simulations, relative to convection-parameterised counterparts and observations.