The Single Column Model

The Met Office Single Column Model is described in UMDP C09 on the Met Office Science Repository web site (login required).

The Met Office Single Column Model (SCM) (UM documentation paper C09) is part of the UM code. At the Met Office it is run on their desktop PCs. This has Rose, Cylc and FCM together with GCOM and the UM shared library. The SCMs are now in Rose suites and can be discovered through the Rosie tool by searching for "SCUM Template": the template suites have this in the projects field. Running the suite is a simple matter as it extracts the code, builds it and runs it all on the same desktop. The SCM runs as a parallel MPI program on a single process. The Met Office suite u-bc355 was chosen as a starting point.

The conversion for NCAS use requires modifications to deal with the PUMA/ARCHER split. Rose, Cylc and FCM are already installed on PUMA, but the SCM executable needs to run on the remote computer ARCHER. This requires changes to the suite so support the remote operation and also changes to the build process to cope with the ARCHER architecture.

The later versions of the SCM UM 10.x+ use the Rose/Cylc framework and are expecting to run in a full UM environment.

To use this you will need an account on PUMA and on ARCHER and also access to the Met Office Science Repository service.

The SCM runs as a parallel process on a computer. It requires the following,

  • an installation of FCM, Rose and Cylc
  • a version of MPI
  • a Fortran 2003 compiler
  • a build of GCOM
  • a build of the shared UM library
  • a version of netCDF

Versions of the SCM prior to UM 11.2 will also need an installation of the shared UM library.

The original intention was to create a version of the SCM that would run on the ARCHER post processor, the non-parallel part of ARCHER. However, the differences between the compute nodes (the parallel part of ARCHER) and the post processor are too great, involving different Intel Xeon chip sets (Westmere for the post processor and Ivy Bridge for the compute nodes) and consequently different cross compilers. It was much simpler to build for the compute nodes.


There is an ARCHER version of the TOGA-COARE SCM model. This is suite u-bf976 which is a UM 11.1 version.

On ARCHER it uses the following modules,

  • Compiler: intel/,
  • MPI: cray-mpich/7.5.5,
  • netCDF: netcdf/4.3.2

Version 11.3 of the TOGA-COARE SCM is also running on ARCHER (u-bj254).

Technical Note on the ARCHER SCM

Running the SCM on your own Personal Computer

The can be done by installing the UM virtual machine on your computer. This is available from the Met Office and the method of installing it is described in Unified Model Virtual Machine Guide - document X10 .

This provides a UM environment and includes FCM, Rose and Cylc as well as all the necessary support software, such as GCOM and the UM shared library.

The installation of the UM virtual machine will take around two hours. Then you will be able to run the same SCM models that the Met Office can.

An example SCM that uses the UM virtual machine is the suite u-bk055 which is a TOGA-COARE SCM at version 11.3. This should run without modification in about ten minutes.

Previous Versions

  1. McGinty

25 June 2019

Last modified 2 years ago Last modified on 25/06/19 15:57:04