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