[RegCNET] Give me a hand, questions about the ctl output file.

[bixq]

Hi, Yan:

General speaking, you'd better read the documentation of GrADS, then
you should understand the questions you raised.

On Fri, 14 Aug 2009, Yan Libin wrote:

> Dear Regcm Lovers,
>
> I've run Regcm-dust well, but encountered some puzzles as following.
>
> Question 1:
> In domain.param file, x and y are setup as:
>      parameter(iy=112)          ! number of grid points in y direction (i)
>      parameter(jx=160)          ! number of grid points in x direction (j)
> But in output ctl file, x and y sums up as:
> xdef 529 linear 45.84 0.2252
> ydef 250 linear 5.1 0.2252
> Why does this happen? Are subgrids results output?

Read the pdef page of the GrADS documentation.

>
> Question 2:
> According to the regcm tutorial, the output file are at sigma levels.
> So zdef should be between 0.0 and 1.0
> But in ctl file,
> zdef 18 levels 1008.68 999.55 985.85 963.02 931.06 889.96 839.73 780.37
> 711.88 638.82 565.76 492.7 419.64 346.58 278.08 218.72 168.49 122.83
> Do these represent the pressure of its sigma level?

In GrADS, the vertical direction is the pressure level (unit: mb). Since
in RegCM, we use sigma, at this moment, you should regard this zdef as
some kind of "fake pressure level". (It roughly works for those ocean 
points at this moment). Of course, you have to do the SIGMA2P conversion
later to have the right pressure level.

You cannot use the sigma value to define zdef, otherwise, GrADS would 
treat them at the very high places.

>
> Any helps will be appreciated!
>
> title RegCM normal output variables
> undef -1e+34
> xdef 529 linear 45.84 0.2252
> ydef 250 linear 5.1 0.2252
> zdef 18 levels 1008.68 999.55 985.85 963.02 931.06 889.96 839.73 780.37
> 711.88 638.82 565.76 492.7 419.64 346.58 278.08 218.72 168.49 122.83

I guess that you should also have pdef line in the GrADS descriptor file.


Regards,
Bi Xunqiang