[ncl-talk] Computing the level of free convection, equilibrium level etc. for CAPE

[Dave Allured - NOAA Affiliate]

Prashanth, please remember to include the mailing list in your replies.

It turns out that there are two different WRF forums.  The other one seems
to be more active.  In particular, there is a modern discussion of CAPE
behavior and parameterization in the post processing/RIP category.

    https://forum.mmm.ucar.edu/

Also note, NCL upgraded the CAPE routine in NCL 6.6.2.  I think that is the
version that Dennis sent.  The older version in 6.5.0 was in fortran 77,
and the results were somewhat different.  I would recommend the newer
version over the older one.

Last time I checked, late last year, the CAPE routine in WRF was identical
to the NCL 6.6.2 version, except for a few "cosmetic" differences.


On Thu, May 5, 2022 at 7:26 AM Prashanth Bhalachandran <
prashanth.bhalachandran at gmail.com> wrote:

> Thanks, Dave. I’ve gone through the various WRF forums but I am unable to
> find what I specifically need. I am a bit weak in Fortran, so I am
> struggling to find answers to the four basic elements (the parcel, the
> environment, the levels of free convection, and neutral buoyancy) needed to
> compute CAPE but I guess with enough persistence, I should extract it from
> the Fortran code that Dennis sent.
>
> Prashanth
>
> On May 4, 2022, at 2:58 PM, Dave Allured - NOAA Affiliate <
> dave.allured at noaa.gov> wrote:
>
> Prashanth, the CAPE routines were copied from the WRF project.  There are
> active discussions about their software in the WRF forums.  I suggest look
> in the Graphics and Post-Processing category.
>
>     https://wrfforum.com
>
> You can probably use the NCL wrap functions to call your own customized
> CAPE fortran routine directly from NCL.
>
>
> On Wed, May 4, 2022 at 3:26 PM Dennis Shea via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
>> NCL developers did NOT develop the underlying fortran codes invoked by
>> 'wrf_cape_3d'
>> NCL developers created only the C interfaces between NCL and the fortran
>> subroutines.
>>
>> Hence, we can not answer your questions. I have attached the fortran code
>> that I think is used by NCL.
>>
>> Good Luck.
>>
>>
>> On Wed, May 4, 2022 at 2:31 PM Sai Prasanth <
>> prashanth.bhalachandran at gmail.com> wrote:
>>
>>> Dear NCL experts,
>>> I am trying to compute the CAPE for the various columns in a cyclonic
>>> storm and I'd like to change the definition of the "environment". As a
>>> result, I'd like to have control over the various steps in the process and
>>> prefer not to directly use the CAPE_3D subroutine. Unfortunately, I can't
>>> seem to figure out how to calculate the integral limits viz. the level of
>>> free convection and the level of equilibrium. I see that the parcel is
>>> defined as the 500 m vertical block within which the various parameters are
>>> averaged. Can you please share the code of wrf_cape_3d or explain in
>>> algorithmic terms how the environment is defined, and how the two levels
>>> that form the integral bounds are computed?
>>>
>>> Thank you,
>>> Prashanth
>>>
>>
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