NCAS Computational Modelling Services


Documentation on how to remove halos from datasets before converting data using CDDS.

Suite u-bo201 is built to remove halos from datasets. The following steps are necessary prior to converting data using CDDS. This suite can be found in the MOSRS repository using rosie go.

Step 1:

Log into JASMIN cylc server (

Step 2:

Copy suite u-bo201 and change two variables within the rose-suite.conf file; HALO_START_DIR and root-dir{work}:


This is where your data sits prior to being put through the de-halo process. The path expects a suite directory which itself contains directories with data files.

The following example shows how to specify your HALO_START_DIR path:

HALO_START_DIR = /gws/nopw/j04/rdf_migrate_vol2/my_username/u-aa123

Suite Structure

2) root-dir{work}

This is the location where the cylc-run/work directory will be created during the run. The cylc-run/work directory is used as an intermediate space to store data files while they are being de-haloed. This must be set to a location on the same group workspace as HALO_START_DIR i.e.


Step 3:

Run the suite.

The suite will start one cycle run per directory being put through the de-halo process. A cycle will fail during ‘file_check’ if it cannot find a corresponding directory.

As part of suite workflow, a cdds-holding directory will be generated which temporarily holds files. NEVER delete anything from the cdds-holding direcory - contact CMS is you suspect a problem.

What you end up with:

1) Your HALO_START_DIR still contains all of your original directories, but these directories now only contain the original versions of .nc files which needed de-haloing.

2) A new directory with the same name as the start directory, but which ends in -cdds (i.e. u-aa123-cdds) . This directory gets created at the start of the suite run at the same path location as the HALO_START_DIR. This will contain all of your data with the new .nc files which have been de-haloed.