Spin‐up of UK Earth System Model 1 (UKESM1) for CMIP6

摘要: For simulations intended to study the influence of anthropogenic forcing on climate, temporal stability Earth's natural heat, freshwater and biogeochemical budgets is critical. Achieving such coupled model equilibration scientifically computationally challenging. We describe protocol used spin‐up UK Earth system (UKESM1) with respect pre‐industrial for use in 6th Coupled Model Intercomparison Project (CMIP6). Due high computational cost UKESM1's atmospheric model, especially when running interactive full chemistry aerosols, primarily parallel configurations using only ocean/land components. ocean, resulting permitted carbon heat contents ocean's volume approach equilibrium over ~5000 years. On land, a ~1000 years brought dynamic vegetation soil reservoirs towards near‐equilibrium. The end‐states these ocean‐ land‐only phases then initialised multi‐centennial period prior this simulation continuing as UKESM1 CMIP6 control (piControl). realism fully‐coupled was assessed range ocean land properties, degree key variables. Lessons drawn include importance consistent interface physics across models (parent) extreme duration required targets, occurrence significant regional drifts despite global‐scale equilibration. Overall, underscores expense involved argues favour future development more efficient techniques.