More On Naming Conventions

 

Some of the basic conventions used in the code have been previously described. We describe a few more of the conventions used in naming variables below:

1. Distinguishing between barotropic vs. baroclinic variables:

   Generally, variables used to describe the barotropic mode have ``0'' attached to the end (e.g. u0, v0). Generally, variables used to describe the baroclinic mode have the suffix ``1'' attached (e.g. u1, v1).

2. Variable designation rhs:

   The designation ``rhs'' refers to ``right-hand side.'' A variable with this designation (e.g. rhsu1, which is the right-hand side of the differential equation) as part of its name lumps together all the non-time-dependent terms of a particular equation. This makes it easier to increment the system a time step.

3. im1 and ip1

   The variable im1 means ``variable i minus one.'' The variable ip1 means ``variable i plus one.'' These are useful for handling the periodic boundary conditions.

4. Radiation flux direction:

   Net longwave radiation flux (FLW) into an atmospheric column is defined such that if , then the whole column absorbs energy. Thus:

   where ``us'' means upwards, at the surface; ``ds'' means downwards, at the surface; and ``ut'' means upwards, at the top-of-atmosphere.

5. dayofmodel variable versus function:

   The label dayofmodel is the name of the variable. With underscores, i.e. day_of_model, the term refers to the function.

Besides the prognostic and diagnostic permanent grid variables, the model also uses some temporary local variables in its computations. Below is an explanation of the names of some of these temporary variables:

u0atC

Located at the same position as u. Variable u0atC represents `` calculated at a `grid center' position.'' Temperature (T1) is located at this location. Variable u0atC is computed as the mean of the two values one half-steps in ``front'' and in ``back'' of the ``grid center.'' Thus, .

vatu

Located at the same position as u. Variable vatu represents ``v calculated at the u position,'' and is computed as the mean of the meridional velocity v at the ``four corners'' surrounding the u point location.

fu

Located at the same j position as u. Variable fu represents the Coriolis parameter evaluated at the latitudinal circle u is located at.

fv

Located at the same j position as v. Variable fv represents the Coriolis parameter evaluated at the latitudinal circle v is located at.

Most variables are dimensioned ( ). However, because of the treatment of the boundaries, some of the model variables are dimensioned a bit differently (see discussion in Section 3.3.1).

Below is a table explaining the meaning of some variables whose function may not be obvious from the variable name and from the conventions described above. These are relatively ``minor'' variables (e.g. not a ``main'' variable like advection) that is specific only to the code, having no direct counterparts in the QTCM1 papers Neelin and Zeng [1] or Zeng et al. [2]. See Section 3.4.2 for a table relating code variables with the notation in the QTCM1 papers.