Articles | Volume 10, issue 4
Geosci. Model Dev., 10, 1487–1520, 2017

Special issue: GA/GL: Decription of the Met Office Unified Model Global Atmosphere...

Geosci. Model Dev., 10, 1487–1520, 2017

Model description paper 11 Apr 2017

Model description paper | 11 Apr 2017

The Met Office Unified Model Global Atmosphere 6.0/6.1 and JULES Global Land 6.0/6.1 configurations

David Walters1, Ian Boutle1, Malcolm Brooks1, Thomas Melvin1, Rachel Stratton1, Simon Vosper1, Helen Wells1, Keith Williams1, Nigel Wood1, Thomas Allen1, Andrew Bushell1, Dan Copsey1, Paul Earnshaw1, John Edwards1, Markus Gross1,2, Steven Hardiman1, Chris Harris1, Julian Heming1, Nicholas Klingaman3, Richard Levine1, James Manners1, Gill Martin1, Sean Milton1, Marion Mittermaier1, Cyril Morcrette1, Thomas Riddick1,4, Malcolm Roberts1, Claudio Sanchez1, Paul Selwood1, Alison Stirling1, Chris Smith1, Dan Suri1, Warren Tennant1, Pier Luigi Vidale1, Jonathan Wilkinson1, Martin Willett1, Steve Woolnough3, and Prince Xavier1 David Walters et al.
  • 1Met Office, FitzRoy Road, Exeter, EX1 3PB, UK
  • 2Centro de Investigación Científica y de Educación Superior de Ensenada, Departamento de Oceanografía Física, Carretera Ensenada-Tijuana 3918, Ensenada BC 22860, Mexico
  • 3National Centre for Atmospheric Science, Department of Meteorology, University of Reading, Reading, RG6 6BB, UK
  • 4Max Planck Institute for Meteorology, Bundesstrasse 53, 20146 Hamburg, Germany

Abstract. We describe Global Atmosphere 6.0 and Global Land 6.0 (GA6.0/GL6.0): the latest science configurations of the Met Office Unified Model and JULES (Joint UK Land Environment Simulator) land surface model developed for use across all timescales. Global Atmosphere 6.0 includes the ENDGame (Even Newer Dynamics for General atmospheric modelling of the environment) dynamical core, which significantly increases mid-latitude variability improving a known model bias. Alongside developments of the model's physical parametrisations, ENDGame also increases variability in the tropics, which leads to an improved representation of tropical cyclones and other tropical phenomena. Further developments of the atmospheric and land surface parametrisations improve other aspects of model performance, including the forecasting of surface weather phenomena.

We also describe GA6.1/GL6.1, which includes a small number of long-standing differences from our main trunk configurations that we continue to require for operational global weather prediction.

Since July 2014, GA6.1/GL6.1 has been used by the Met Office for operational global numerical weather prediction, whilst GA6.0/GL6.0 was implemented in its remaining global prediction systems over the following year.

Short summary
Global Atmosphere (GA) configurations of the Unified Model (UM) and Global Land (GL) configurations of JULES are developed for use in any global atmospheric modelling application.

We describe a recent iteration of these configurations: GA6/GL6. This includes ENDGame: a new dynamical core designed to improve the model's accuracy, stability and scalability. GA6 is now operational in a variety of Met Office and UM collaborators applications and hence its documentation is important.