################################
Parameters on the vertical axis
################################

.. role:: bash(code)
   :language: bash

.. include :: caution-grid.rst

vcoord.nc
----------

The actual pressure coordinates :bash:`ap` and :bash:`bp` are read in vcoord.nc by subroutine :bash:`dynstate1` (in :bash:`dyn3d/dynstate0.F90`). See :doc:`vcoord format<coordfiles>`: they are given on NLEV+1 levels with zeros for NLEV+1 XXcheck!!XX.

In files written by LMDz-SACS for future re-use as initial conditions, variable :bash:`presnivs` is written for information: it contains the pressures of the middles of the NLEV layers (see computation in :bash:`dyn3d/disvert.F90`).

Remark: he surface is level number 1, the top of the  atmosphere is level number NLEV.