.. _attributes:

==================================
Application-independent attributes
==================================

The following attributes are obtained from the respective driver and
available to all components that the driver uses.  In the case of
CESM/NorESM, the driver ingests these attributes from the
``nuopc.runconfig`` file.  In the case of UFS, the UFS driver ingests
these attributes from the ``ufs.configure`` file.  The list of
attributes below are separated into application independent attributes
and at this time additional attributes required by CESM. There are no
UFS-specific attributes required by the UFS application.


General
-------

**coupling_mode** (required)

  The coupling_mode attribute determines which
  ``esmFlds_exchange_xxx_mod.F90`` is used by CMEPS and is also
  leveraged in some of the custom calculations in the ``prep``
  modules.

  The currently supported values for ``coupling_mode`` are ``cesm``, ``noresm``, ``ufs.(frac,nfrac).(aoflux)``, and ``hafs``.

Scalar attributes
-----------------

**ScalarFieldCount**
  The maximum number of scalars that are going to be communicated
  between the mediator and a component.  Currently scalar values are
  put into a field bundle that only contains an undistributed
  dimension equal to the size of ``ScalarFieldCount`` and communicated
  between the component and the mediator on the `main task` of each
  component.

**ScalarFieldName** (required)
  This is the name of the scalar field bundle. By default it is ``cpl_scalars``.

**ScalarFieldIdxGridNX**, **ScalarFieldIdxGridNY** (required)
  The global number of longitude and latitude points. For unstructured grids::

    ScalarFieldIdxGridNY = 1
    ScalarFieldIdxGridNX = global size of mesh

  For cases where ``ScalarFieldIdxGridNY`` is not 1, this scalar data
  is needed by the mediator for the history output.

**ScalarFieldIdxNextSwCday** (optional)
 Send by the atmosphere component to specify the calendar day of its
 next short wave computation.  This is subsequently used by other
 components (e.g. cesm-land and sea-ice) in determining the zenith
 angle for its albedo calculation. It is also used in the mediator
 routine ``med_phases_ocnalb_mod.F90`` to determine the zenith angle
 in the ocean albedo calculation.

Mediator history and restart attributes
---------------------------------------

**history_option**, **history_n** (required)
  Determines the write frequency for a mediator history file (see :ref:`mediator history writes <history>`).
**restart_option**, **restart_n** (required)
  Determines the write frequency for a mediator restart file (see :ref:`mediator restart writes <restart>`).
**read_restart** (required)
  Determines if a mediator restart file is read in.