Using the UM dynamical cores to reproduce idealised 3D flows

TL;DR

This paper demonstrates that both current and next-generation UK Met Office dynamical cores accurately reproduce idealised large-scale 3D flows, with improvements in the newer core providing more detailed planetary circulation features.

Contribution

The study validates the performance of the UK Met Office's dynamical cores in idealised flow tests and highlights the improvements in the ENDGame core over New Dynamics.

Findings

Both dynamical cores reproduce idealised flows consistently.

Simplified equations still produce matching large-scale flows.

ENDGame core shows improved detail in planetary circulations.

Abstract

We demonstrate that both the current (New Dynamics), and next generation (ENDGame) dynamical cores of the UK Met Office global circulation model, the UM, reproduce consistently, the long-term, large-scale flows found in several published idealised tests. The cases presented are the Held-Suarez test, a simplified model of Earth (including a stratosphere), and a hypothetical tidally locked Earth. Furthermore, we show that using simplifications to the dynamical equations, which are expected to be justified for the physical domains and flow regimes we have studied, and which are supported by the ENDGame dynamical core, also produces matching long-term, large-scale flows. Finally, we present evidence for differences in the detail of the planetary flows and circulations resulting from improvements in the ENDGame formulation over New Dynamics.