The Met Office Unified Model Global Atmosphere 8.0 and JULES Global Land 9.0 configurations

作者：Martin Willett, Melissa Brooks, Andrew Bushell, Paul Earnshaw, Samantha Smith, Lorenzo Tomassini, Martin Best, Ian Boutle, Jennifer Brooke, John M. Edwards, Andrew D. Elvidge, Kalli Furtado, Catherine Hardacre, Andrew James Hartley, Alan J. Hewitt, Ben Johnson, ADRIAN C. LOCK, Andy Malcolm, Jane P. Mulcahy, Eike Müller, Ian A. Renfrew, Heather Rumbold, G. G. Rooney, Alistair Sellar, Masashi Ujiie, Annelize van Niekerk, Andy Wiltshire, Michael Whitall · 发表于：Geoscientific model development · 年份：2026 · DOI：10.5194/gmd-19-1473-2026 · 被引用次数：2 · 研究领域：Climate variability and models、Meteorological Phenomena and Simulations、Atmospheric aerosols and clouds

Abstract. We describe Global Atmosphere 8.0 and Global Land 9.0 (GA8GL9) that are science configurations of the Met Office Unified Model and Joint UK Land Environment Simulator (JULES) land surface model developed for use across weather and climate timescales. GA8GL9 builds upon GA7GL7. It not only consolidates the changes made for the climate branch configuration GA7.1GL7.1 (the atmosphere and land components of the physical model used in HadGEM3-GC3.1, UKESM1 and UKESM1.1 which were all used in the Met Office's CMIP6 submissions) and NWP branch configuration GA7.2GL8.1 (the operational global NWP model at the Met Office between 2019 and 2022), but also includes developments to most areas of the science. Some of the key changes include: prognostic-based entrainment, which adds convective memory and improves precipitation rates and spatial structures; time-smoothed convective increments, which improves the convection-dynamics coupling and greatly reduces the detrimental dynamical effects of convective intermittency; a new riming parametrisation, which increases the amount of supercooled water and hence reduces Southern Ocean biases; and a package of land surface changes, which improves the forecast of near-surface fields and hence removes the need for the aggregate surface tile in NWP applications. Several changes are made that reduce numerical artefacts and improve the numerical stability of the model. The NWP and climate performance of GA8GL9 is evaluated against the previo...