Unified Model

The Met Office Unified Model (UM) is the name given to the suite of numerical modelling software developed and used at the Met Office. The UM modelling software is designed so that the model can be run in atmosphere-only (global or limited area), ocean-only or in coupled atmosphere-ocean mode.

The Unified Model is used by the UK Met Office for operational numerical weather prediction and by the Hadley Centre for Climate Prediction and Research to simulate and predict the Earth's climate.

Running the UM

The UM is a complex software sytem so a new user should read the documentation available on this web site and complete the UM training provided by NCAS.

The UM software needs to be properly installed so that the scripts, tools, code and files for running an experiment are available. NCAS installs and maintains the supported UM versions on the UK national high performance computers. All NCAS researchers can use the UM on these services, details of getting accounts can be found here

Instructions for running a UM experiment on ARCHER can be found at the following links:

UM experiments need input files to run and they create output files for diagnosing the experiment. NCAS has created a set of tools and utilities, to supplement the standard ones from the UK Met Office, to support the creation, manipulation and use of these UM files.

UM versions

The UM undergoes significant changes as new scientific enhancements are introduced or new features are added, and so the Met Office release new versions regularly (approx. 3-4 times a year). NCAS-CMS only supports a subset of the versions that have been released. See the supported versions page for the list of supported UM versions and platforms.

From UM version 10.0, the old UM user interface (UMUI) was replaced by the Rose/cylc application management and work flow system. This provides a much more flexible and powerful way of controlling UM experiments.

Documentation relating to new UM versions (from vn10.0), including the UM User Guides, is available on the Met Office Science Repository Service (MOSRS) here. Note you must be registered to access this service. Contact us for information on getting an account. Documentation for older UM versions (before vn10.0) is available here.

UM Configurations

Climate Configurations

In order to run the climate model, users need to have access to a set of files that will enable them to run a particular scientific version of the climate model (describing exactly the physical and dynamical choices within the UM system). Two climate model 'families' (HadGEM2 and HadGEM3) are routinely used by academic researchers. Only HadGEM3 is still actively developed by the Met Office Hadley Centre. These models differ very significantly in terms of their numerical and physical formulation. The Met Office have released several configurations of these models and NCAS-CMS have ported certain "standard" configurations to the National HPC system ARCHER.

See UM Configurations page for full details.

Parallel Suites and NWP Configurations

Nested limited area models can easily be set up using the Met Office Nesting Suite. These are Rose suites and can be run on ARCHER and Monsoon, allowing scientists to define up to five nested domains, a choice of science configurations and easy ancillary file generation for the chosen domains.

Mesoscale Modelling

Methods for getting UM start dumps from various computers can be found on the Mesoscale Modelling page.

The Single Column Model

The Single Column Model page explains how to run the Met Office Single Column model on various computers.

Source Code and STASHmaster Browsers

The UM Fortran source code is available to to view via the UM Trac Code Browser or alternatively, the UM source code has been converted into a hyperlinked website.

See UM Source Code Browsers

Last modified 3 years ago Last modified on 01/07/19 09:42:11