JULES is available to anyone for non-commercial use, free of charge.


JULES is available to anyone for non-commercial use, free of charge. However, please note the JULES licence conditions, the JULES Fair Use and Publication Policy and the MOSRS user terms and conditions.

Please also be aware of additional licencing associated with code development. No code can be committed to the JULES trunk or any branch for which we do not have the permission to use under its specific licence. Please contact the UM Systems Team for guidance prior to committing new code to the repository. Note that some parts of the JULES codebase already have differing licencing. Please refer directly to the source code.


For the current version of JULES, please download from the MOSRS using FCM (see Getting Started) and see the JULES TRAC and documentation/release notes.

Release Date VERSION

Code review deadline

JULESvn7.7 (not yet released)
5-JUL-24 JULESvn7.6
10-APR-24 JULESvn7.5
1-NOV-23 JULESvn7.4
27-JUN-2023 JULESvn7.3
29-MAR-2023 JULESvn7.2
29-NOV-2022 JULESvn7.1
22-JUL-2022 JULESvn7.0
28-FEB-2022 JULESvn6.3
4-NOV-2021 JULESvn6.2
8-JUL-2021 JULESvn6.1
2-MAR-2021 JULESvn6.0
19-NOV-2020 JULESvn5.9
10-JUL-2020 JULESvn5.8
27-FEB-2020 JULESvn5.7
25-OCT-2019 JULESvn5.6
25-JUN-2019 JULESvn5.5
1-MAR-2019 JULESvn5.4
2-NOV-2018 JULESvn5.3
29-JUN-2018 JULESvn5.2
28-FEB-2018 JULESvn5.1
31-OCT-2017 JULESvn5.0
23-JUN-2017 JULESvn4.9
24-FEB-2017 JULESvn4.8
29-OCT-2016 JULESvn4.7
27-JUN-2016 JULESvn4.6
25-FEB-2016 JULESvn4.5
27-OCT-2015 JULESvn4.4
19-JUN-2015 JULESvn4.3 (and vn4.3.1 released 15-JUL-2015, vn4.3.2 released 28-AUG-2015)
27-FEB-2015 JULESvn4.2
31-OCT-2014 JULESvn4.1 (since vn4.1 each JULES version has been linked to a particular UM version, as you can see from the revision numbers)
1-JUL-2014 JULESvn4.0
21-AUG-2013 JULESvn3.4 (and vn3.4.1 released 9-OCT-2013)
10-APR-2013 JULESvn3.3
20-NOV-2012 JULESvn3.2
28-JUN-2012 JULESvn3.1
28-FEB-2011 JULESvn3.0
  Logo changed from

JULES old logo
JULES new logo
24-NOV-2010 JULESvn2.2
29-SEP-2009 JULESvn2.1 (and vn2.1.1 released 5-JAN-2010, vn2.1.2 released 2-FEB-2010)
10-JUL-2007 JULESvn2.0

JULESvn1.0 released at the JULES Launch meeting (see announcement article Blyth et al. (2006) on pp.9-11 and the overview).

Original website's welcome page
Original website's welcome page



JULESvn0 frozen (essentially a combination of TRIFFID and MOSESv2.2).

Note that in some sites the name "MOSES" is still used despite its replacement by "JULES" in 2005 and refers to the current version of the former MOSES code within the UM. For example, the JulesModel User Guide from 2009 mentions "MOSESvn7.1", but this was really only a name for some MOSES code extracted from UM7.1 (i.e. basically JULESvn2.0 code).

AUG-2001 MOSES v2.2 (Essery et al. 2001, essentially this was v2.0 rewritten slightly to accommodate other changes in the Unified Model). See Valdes et al. (2017) for a detailed description of MOSES versions 1.0, 2.0, 2.1 and 2.2.
JAN-2001 Top-down Representation of Interactive Foliage and Flora Including Dynamics (TRIFFID) model (Cox 2001)
1999 MOSES v2.0 (Essery et al. 2003, J Hydromet)
1997 Met Office Surface Exchange Scheme (MOSES) v1.0 (Cox et al. 1999, Clim Dyn)

Code development

Code development is not covered on this website: please see the JULES TRAC for comprehensive resources (starting with the "Developing JULES" section there), but here are a few notes:

  • The best place to start is with Kerry Smout-Day's Developer tutorials here. All proposed changes to the JULES code must follow the Working Practices for JULES development (broadly summarised by the flow diagram shown here) and the JULES Upgrade Procedures. See especially the steps required for adding new science options, and note that in almost all cases you will need to update the Rose meta data and provide a rose upgrade macro.
  • In addition to online tutorials, there are Rose/Cylc and RoseUM training courses held either at the Met Office in Exeter or NCAS in Reading regularly throughout the year.
  • JULES does have a short list of known 'structural' limitations here, but this is not intended as a list for users to add to: if you know of any errors or limitations then the idea is that you rather put them on the JULES TRAC under individual tickets. If you are aware of any defect in the model, or have ideas for an enhancement, then please help the community by raising a ticket about it. For larger issues, you might want to start up a working group or PEG for the issue (JULES PEGs or JPEGs were discussed on 28th June 2017 in Exeter).
  • By the way, Kerry Smout-Day has done these great 'maps' of the JULES code and call paths of the individual subroutines (for JULESvn4.7).
JULES code development workflow diagram
JULES code development workflow diagram