vn3.1

LFRic Apps vn3.1 release notes

Key Changes

• Fixes to incremental builds when using the local_build.py script. #162
• Checkpoint dumps for NWP configurations with glomap_mode=dust_and_clim will additionally include ancil data soil_clay, soil_sand and dust_mrel. #202
• Upgrades to GungHo linear and adjoint models including multigrid preconditioning, boundary layer drag scheme and optimisation of transport and timestepping algorithm.
• MPI ranks for cubed-sphere runs are no longer limited to a factor of 6, and can now run with a factor of 2 or 3. #138
• Tanget Linear model computational improvements (split-Method of Lines, fixed linearisation state and 32-bit precision).
• Better testing of the validity of the linearisation (updated configuration for the linear integration tests).
• A new linear model boundary layer scheme (to match the UM).

Breaking Changes

These changes will affect suites upgrading to this release
* No known breaking changes at this release.

Known Issues

• Adjoint tests have been showing some instability that appears as an intermittent failed tolerance check.
• At vn3.1 an issue with some upgrade macro chains has been identified. This has been fixed, and the stable branch updated, with vn3.1.1 and 2026.03.2 tags added. Please see this announcement for details

Linked Changes

This release is part of the 2026.03.1 Simulation Systems Release.. All
codebases required by LFRic Apps, including LFRic Core, JULES, UKCA etc, have been tagged 2026.03.1.

What's Changed

• Create initial documentation by Andrew Coughtrie (@andrewcoughtrie) in #2
• add rose-stem docs by James Bruten (@james-bruten-mo) in #5
• Correct link to simulation-systems discussions by Björn Fock (@BHFock) in #6
• remove incorrect line by James Bruten (@james-bruten-mo) in #7
• #8 PSyclone transformation scripts documentation by Oakley Brunt (@oakleybrunt) in #9
• Add new option task option: task_ranks_depth_pad by Benjamin Went (@MetBenjaminWent) in #10
• Update transmute docs for Developers working with Transmute PSyclone scripts by Benjamin Went (@MetBenjaminWent) in #15
• Add banner by Jenny Hickson (@jennyhickson) in #17
• Add link to lfric_core docs to front page by Andrew Coughtrie (@andrewcoughtrie) in #18
• Add accessibility statement by Jenny Hickson (@jennyhickson) in #19
• Split workflows by Andrew Coughtrie (@andrewcoughtrie) in #16
• add local build instructions by James Bruten (@james-bruten-mo) in #21
• Update issue templates by Andrew Coughtrie (@andrewcoughtrie) in #24
• Lfric apps rose stem by James Bruten (@james-bruten-mo) in #20
• Moci port by James Bruten (@james-bruten-mo) in #27
• lfric_atm checkpoint documentation by Steve Mullerworth (@stevemullerworth) in #22
• GitHub files by James Bruten (@james-bruten-mo) in #28
• change to c48 by James Bruten (@james-bruten-mo) in #32
• add cla files by James Bruten (@james-bruten-mo) in #33
• Prerelease v3.0 by Jenny Hickson (@jennyhickson) in #35
• Release vn3.0 by Jenny Hickson (@jennyhickson) in #37
• Stable to Main, vn3.0 by James Bruten (@james-bruten-mo) in #38
• Docs deploy only triggers on upstream by mo-marqh in #39
• fix local build script by James Bruten (@james-bruten-mo) in #43
• Remove user contact question from issue template by Yaswant Pradhan (@yaswant) in #63
• Signed CLA by Oakley Brunt (@oakleybrunt) in #78
• Check config name by Mike Hobson (@mike-hobson) in #67
• Add Harry Shepherd to CONTRIBUTORS.md by Harry Shepherd (@harry-shepherd) in #96
• Reformat pull request template by Yaswant Pradhan (@yaswant) in #109
• update symlink by James Bruten (@james-bruten-mo) in #102
• raise error successfully from extract_source by James Bruten (@james-bruten-mo) in #122
• Hotfix to rose-stem suite by Jenny Hickson (@jennyhickson) in #131
• Fixing adjoint failures with transport log_space config variable set to true by DrTVockerodtMO in #71
• Add workflow to block direct merges to the stable branch by Yaswant Pradhan (@yaswant) in #140
• cla signed by Benjamin Went (@MetBenjaminWent) in #147
• Fix coupled model with 32bit compilation by Tim Graham (@timgraham-Met) in #143
• buffer_size_factor: fix broken XIOS attribute name in XML configs by mo-marqh in #144
• Sign contributors by Alistair Pirrie (@mo-alistairp) in #155
• Add project workflow by James Bruten (@james-bruten-mo) in #117
• Timing Mod wrapper rewrite by Jed Baker (@jedbakerMO) in #80
• Update UKCA initialisation for dust only to include segment size by Oakley Brunt (@oakleybrunt) in #83
• update gitignore by James Bruten (@james-bruten-mo) in #75
• Gregory-Rowntree convection - PSyclone optimisation and conversion from CELL_COLUMN to DOMAIN kernel by Ricky Olivier (@ricky-lv426) in #99
• Remove use of deprecated XIOS context API by Ed Hone (@EdHone) in #183
• Stochastic Physics CPU and GPU Optimizations - NGARCH by Jason (Junwei) Lyu (@jasonjunweilyu) in #65
• update jedi owners by James Bruten (@james-bruten-mo) in #173
• Introducing cache for adjoint lookup tables by DrTVockerodtMO in #72
• Performance test config by mo-marqh in #82
• Bug in AOD diagnostics by Alan J Hewitt (@alanjhewitt) in #94
• Removing populate_graph_lfricinputs.cylc by Lottie Turner (@mo-lottieturner) in #54
• Update gitattributes diff to fortran-free-form by Andrew Coughtrie (@andrewcoughtrie) in #190
• Align adjoint_tests to linear_model by Tom Hill (@tom-j-h) in #123
• Fix Gungho Plots by Thomas Bendall (@tommbendall) in #74
• Transmute explicit no Transformation list and global.py by Benjamin Went (@MetBenjaminWent) in #56
• Only build docs when docs files changed by Andrew Coughtrie (@andrewcoughtrie) in #198
• Improve negative mass error message by Thomas Bendall (@tommbendall) in #187
• Log to rank zero only by default by Thomas Bendall (@tommbendall) in #186
• #81: Fix unallocated arrays in ukca_volcanic_so2 by Mohit Dalvi (@mcdalvi) in #133
• Calipers performance25 by mo-marqh in #176
• Add standard suites by James Bruten (@james-bruten-mo) in #203
• Add science guide section to documentation. by Andrew Coughtrie (@andrewcoughtrie) in #204
• Migrate metadata jules_model_environment remainder of jules_surface to jules-shared by Maggie (@maggiehendry) in #181
• Add a COSP timestep so diagnostics can be sampled less often by James Manners (@mo-jmanners) in #158
• Some of Boundary Layer PSyclone-d by Benjamin Went (@MetBenjaminWent) in #57
• Weekly test fix - remove duplicate iodef.xml entry for cell_area field by Ed Hone (@EdHone) in #209
• Speed-up of adjoint transport by DrTVockerodtMO in #145
• Replace model rh_crit with fixed value from config in glomap_aerosol by Steve Mullerworth (@stevemullerworth) in #193
• Added Stability with Advective Tracers by James Kent (@jameskent-metoffice) in #171
• Remove redundant info from mesh configs by cjohnson-pi in #153
• Add support for monsoon 3 by Sam Clarke-Green (@t00sa) in #166
• jelf adjoint test tolerance namelist variable by Tom Hill (@tom-j-h) in #132
• Generation of lfric2lfric lbcs by Juan Manuel Castillo Sanchez (@ukmo-juan-castillo) in #55
• Correct the sample_physics_winds_correction option by Thomas Bendall (@tommbendall) in #69
• Add link to milestones in readme by Andrew Coughtrie (@andrewcoughtrie) in #235
• update trigger project workflow by James Bruten (@james-bruten-mo) in #237
• Stochastic Physics Fixes by Thomas Bendall (@tommbendall) in #148
• Floating-point precision conversions in jelf by Tom Hill (@tom-j-h) in #142
  ...

vn3.0

LFRic Apps vn3.0 release notes

Full Changelog: vn2.2...vn3.0

This is the first GitHub release of LFRic Apps. Please see the refreshed Working Practices for details on how to migrate branches and work with GitHub.

Key Changes

• Added flexibility for checkpointing at multiple points during a model run, defined in configuration with a list of times in ticket:981
• Various optimisations to the physics code.
• IAU Capability for SST and JADA in ticket:885 and ticket:886.
• Dynamical core stability improvements through ticket:878 and ticket:953, which have a really reduced model failures related to divergent winds
• Regional model stability improvements through ticket:750 and ticket:851
• Improved moist thermodynamics through ticket:827
• Rose stem updates to the lfric_atm and transport apps in ticket:845 and ticket:939
• Draft sphinx based documentation hosted on GitHub

Linked Codebases

This release is part of the 2025.12.1 Simulation Systems Release.. All codebases required by LFRic Apps, including LFRic Core, JULES, UKCA etc, have been tagged 2025.12.1.