Process Development¶

This section covers developing new processes and schemes for CATChem. See the CATChem User Guide for a description of all processes available in CATChem.

Quick Links¶

Architecture Overview - Understanding process design patterns
Process Generator - Complete guide to using the automated process generator
Creating Custom Processes - Manual process development
Templates and Patterns - Code templates and best practices
Testing Processes - Testing strategies and frameworks

Overview¶

CATChem processes are modular components that implement specific atmospheric transport, chemical, emission, or loss schemes. Each process follows a standardized interface and lifecycle.

Process Architecture¶

All processes inherit from the base ProcessInterface and must implement init, run, and finalize. Column-based processes should extend ColumnProcessInterface.

module MyProcess_Mod
  use ProcessInterface_Mod, only: ColumnProcessInterface
  use StateManager_Mod, only: StateManagerType
  use VirtualColumn_Mod, only: VirtualColumnType
  implicit none

  type, extends(ColumnProcessInterface) :: MyProcessType
    ! Private data members
  contains
    procedure :: init => MyProcess_init
    procedure :: run => MyProcess_run
    procedure :: finalize => MyProcess_finalize
    procedure :: run_column => MyProcess_run_column
  end type

contains

  subroutine MyProcess_init(this, container, rc)
    class(MyProcessType), intent(inout) :: this
    type(StateManagerType), intent(inout) :: container
    integer, intent(out) :: rc
    ! Initialize process
  end subroutine

  subroutine MyProcess_run(this, container, rc)
    class(MyProcessType), intent(inout) :: this
    type(StateManagerType), intent(inout) :: container
    integer, intent(out) :: rc
    ! 3D operations (before/after column processing)
  end subroutine

  subroutine MyProcess_finalize(this, rc)
    class(MyProcessType), intent(inout) :: this
    integer, intent(out) :: rc
    ! Clean up resources
  end subroutine

  subroutine MyProcess_run_column(this, column, container, rc)
    class(MyProcessType), intent(inout) :: this
    type(VirtualColumnType), intent(inout) :: column
    type(StateManagerType), intent(inout) :: container
    integer, intent(out) :: rc
    ! Process a single column
  end subroutine

end module

Creating New Processes¶

To create a new process, follow the Creating Custom Processes guide.

Scheme Development¶

Schemes implement specific algorithms within a process. See the seasalt process for an example of how to structure schemes.

Testing Processes¶

All new processes must include unit and integration tests. See the Testing Processes guide for more information.

Documentation¶

All new processes must be documented using Doxygen-style comments.