SPF ExCALIBUR: UK Chemistry and Aerosol (UKCA) Model Design

Tender description

UKCA is responsible for predicting the evolution of a large number of atmospheric chemical and aerosol species and their impact on the climate, weather, and air quality. It is therefore an essential model component across all time scales and is also one of the most expensive components of the system. This activity, which is part of the Weather and Climate Work Package 1, will seek to dramatically improve the computational performance of the model as well as improving its flexibility in terms of its ease of deployment to different architectures and general usability. This will be achieved in two stages. The first will isolate the UKCA code base from the Unified Model (UM) in its own repository, develop a stand-alone UKCA driver (e.g. a box model which can drive aerosol and chemistry processes) and implement a clear testing framework. This will pave the way for the coupling of the revised UKCA to the new system (LFRic) including use of a reduced resolution facility, work to be performed as part of Weather and Climate Work Package 3. It will also facilitate the second stage of work. This stage will analyse the performance bottlenecks, propose a redesign of the appropriate aspects and then implement and test those changes to address the key bottlenecks. Keywords: Research