Code Repositories#

LFRic Atmosphere is built from several GitHub repositories. The LFRic Apps Repository is the home for LFRic-based science applications and libraries, including the Momentum Atmosphere model application and the GungHo dynamical core. Those applications are based on infrastructure provided by LFRic Core Repository. Larger science packages are kept in their own repositories and are pulled into an atmosphere build through the versions recorded in LFRic dependencies.

Repository map#

Repository or area	What it contains	When you are likely to use it
LFRic Apps Repository	The home for LFRic-based science applications and libraries, including the Momentum Atmosphere model application and the GungHo dynamical core. These applications use the infrastructure developed in LFRic Core Repository.	Start here when working with the atmosphere model, science application configurations, or practical examples in this training.
LFRic Core Repository	The underlying infrastructure for the Momentum Atmosphere model and associated applications.	Use this when a change belongs in the shared LFRic infrastructure rather than in the atmosphere model or another science application.
Science component repositories	Larger science packages such as CASIM, JULES, SOCRATES, and UKCA. These are versioned independently and connected to LFRic Atmosphere through dependencies and interfaces.	Check these when a change is in a separately maintained science package rather than in LFRic Apps or LFRic Core.

LFRic Apps and science applications#

The LFRic Apps Repository is the GitHub home for LFRic-based science applications and libraries. Its README identifies the Momentum Atmosphere model application and the GungHo dynamical core as examples of the applications and libraries it contains. These are built on the infrastructure developed in LFRic Core Repository.

Table 4 Useful LFRic Apps areas#
Link	What it points to
LFRic Apps applications	The application directories in LFRic Apps.
LFRic Atmosphere application	The Momentum Atmosphere model application area, including source, examples, metadata, build files, and optimisation material.
GungHo	The GungHo dynamical core application area, identified by the LFRic Apps README as one of the key LFRic-based applications.
Linear model	The linear model application area, including source, examples, rose-meta, and optimisation material.
LFRic to LFRic	The Lfric2Lfric miniapp area. Its documentation describes regridding and boundary-condition creation capabilities for LFRic meshes.
LFRic inputs	The LFRic inputs application area, including source and supporting scripts.
LFRic Apps science code	Science code maintained directly in LFRic Apps, including adjoint, GungHo, linear, physics schemes, and shared science areas.
Model Physics	The LFRic Apps physics schemes area.
LFRic interfaces	Interface code connecting LFRic Apps to coupled, JEDI LFRic, JULES, physics schemes, and SOCRATES interface areas.
LFRic dependencies	The dependency file that records the selected versions of external repositories used by a particular LFRic Apps checkout.

Note

For most practical work in this training, clone and work in LFRic Apps Repository. Move to LFRic Core Repository or a science component repository only when the change clearly belongs there.

Science component repositories#

Some science packages are large enough, or shared enough, to live in their own repositories. They are still compiled with LFRic Atmosphere into a single executable. The versions used by a particular LFRic Apps checkout are defined in LFRic dependencies.

Table 5 Science code included in LFRic Atmosphere with individual repositories#
Science code	Description	Repository
CASIM	Cloud and AeroSol Interacting Microphysics, described by its README as a component of the Met Office - NERC Cloud Model (MONC)	CASIM repository
JULES	Joint UK Land Environment Simulator: the land surface model used for surface fluxes, hydrology, carbon cycle, and vegetation	JULES repository
SOCRATES	Suite Of Community RAdiative Transfer codes based on Edwards and Slingo	SOCRATES repository
UKCA	United Kingdom Chemistry and Aerosols Project: a UK community atmospheric chemistry-aerosol model for climate and environmental change research	UKCA repository

Choosing the right repository#

If you are unsure where a change belongs, start by asking what owns the code you need to edit:

model applications, atmosphere examples, LFRic science code, interfaces, and dependency versions usually belong in LFRic Apps Repository;
reusable infrastructure that is shared by LFRic applications usually belongs in LFRic Core Repository;
standalone science packages such as CASIM, JULES, SOCRATES, and UKCA usually belong in their own repositories, with LFRic Apps updated only where an interface or dependency version also needs to change.

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