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Boundary condition inputs
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The BOUN_CONCS files contain the concentration fields in molecules/cm3 at the lateral borders of the model's grid and at the top of the domain. Among the species in BOUN_CONCS, only those which are listed in the ACTIVE_SPECIES file of the :doc:`chemical scheme<chemistry>` are used. If no concentrations are provided for a given species, its lateral and top concentrations are set at 1d-17 (see :bash:`iniboun`). 

.. warning:: check that no species is set at null boundary concentrations due to forgetting it in BOUN_CONCS since no error is then raised.


The boundary concentrations provided in dry air mole fractions can be converted into total air mole fractions (in :bash:`master_locvalues`) for correct use by CHIMERE, following the specifications of the user in the ACTIVE_SPECIES file of the :doc:`chemical scheme<chemistry>`. The units are assumed to be ppb XX PUT A CHECK OF THIS?XXX

See also :doc:`the fields plugins for CHIMERE </documentation/plugins/fields/chimere_icbc>` for documentation on these files and the information to provide to the CIF to generate them.

The format of BOUN_CONCS is as follows, with PP, NVERTI, NZONAL and NMERID given the relevant values, NS the number of species in the file (i.e. the same list of species for lateral boundaries and the top),  NHBLAT is the number of cells in the lateral borders at one level = (NZONAL + NMERID) * 2

.. literalinclude:: dump_boundconcs.txt
     :language: text

Important points: 
  - the actual length of record is PP+1 since one hour more than the covered period is required for time interpolation within the last simulation hour.
  - the dates are written in a fixed format on 19 characters (DateStrLen): YYYY-MM-DD_HH:mm:ss
  - the species names can be as long as SpStrLen = 23 characters
  - the concentrations must be written as :bash:`double` and NOT :bash:`float` to ensure enough precision for the adjoint.