Mesoscale organisation of tropical convection

Recent research has shown that the spatial organisation of convection (and hence clouds) at the mesoscale (20-200km) dramatically affects the Earth’s energy balance and hydrological cycle. This raises the question as to how the organisation of convection will change with warming, and how it will influence the climate. A poor understanding of the physical drivers of the mesoscale organisation of convection, compounded by an inability to simulate and observe such processes, has hampered our ability to articulate this challenging question, let alone answer it. In MAESTRO I propose to develop observational approaches and analysis frameworks specifically designed to test mechanisms hypothesized to control the mesoscale organisation of both shallow and deep convective clouds. Advances in airborne remote sensing will be exploited to map the spatial structures of clouds and water vapor, to interpret their coupling through the analysis of coherent structures within the clear-air environment around clouds, and to understand their dependence on environmental conditions. This will help understand why and how convective clouds organise at the mesoscale, why the organisation co-varies with water vapor, clouds and radiation locally and remotely, and why it co-varies with climate conditions. By connecting observations from the airborne measurements to satellite observations and meteorological analyses, the generality of the insights from the field measurements will be tested and tempered. Finally, observational insights will be used to assess the new and emerging generation of climate models whose resolution is fine enough to represent the mesoscale organisation of convection and its interaction with climate. MAESTRO will lead to new experimental techniques for studying atmospheric processes, to an improved conceptualization of the interplay between convective organisation and climate, and to a critical assessment of the new generation of climate models for climate change studies.