Fix comments in hybrid coordinate registry

[davegill]

TYPE: text only

KEYWORDS: hybrid comments

SOURCE: Found by Kezhen Chong (Georgia Institute of Technology), fixed internally

DESCRIPTION OF CHANGES:
Modify the comments in registry.hyb_coord to correctly define c4f and c4h. Originally, the value
of the pressure at the model lid (ptop) was included in the description of the computation of
the C4F and C4H 1d arrays as an added term. Following is the source code showing no such term.

   !  c4 is a function of c3 and eta.

   DO k=1, kde
      c4f(k) = ( znw(k) - c3f(k) ) * ( p1000mb - p_top )
   ENDDO

   !  Now on half levels, just add up and divide by 2 (for c3h).  Use (eta-c3)*(p00-pt) for c4 on half levels.

   DO k=1, kde-1
      c4h(k) = ( znu(k) - c3h(k) ) * ( p1000mb - p_top )
   ENDDO

ISSUE:
Fixes #1050

LIST OF MODIFIED FILES:
modified: Registry/registry.hyb_coord

TESTS CONDUCTED:

• Text only in comment in a registry file, no tests required.

[davegill]

@kchong75

1. Please provide your name and affiliation for our commit message.
2. Would you verify if this PR corrects the problem.

[kchong75]

Also, at the 4th line of registry.hyb_coord, it is "Pc = Pds - Pt", according to the variable definition below, should it be "Pc + Pcb = Pds - Pt" ?
Thank you!

[davegill]

@kchong75
Would you please provide your name and affiliation so that we credit you in our release message.

[kchong75]

Hi Dave, I am Kezhen Chong from Georgia Institute of Technology. Thank you, Kezhen Get Outlook for Android<https://aka.ms/ghei36>

…

________________________________ From: Dave Gill <notifications@github.com> Sent: Monday, January 13, 2020 2:00:49 PM To: wrf-model/WRF <WRF@noreply.github.com> Cc: Chong, Kezhen <kezhenchong@gatech.edu>; Mention <mention@noreply.github.com> Subject: Re: [wrf-model/WRF] Fix registry comments on c4f and c4h (#1051) @kchong75<https://github.com/kchong75> Would you please provide your name and affiliation so that we credit you in our release message. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#1051?email_source=notifications&email_token=ALSX5RYZNWMLISOST2XYLLTQ5S26DA5CNFSM4KBNYWX2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEIZ4ILI#issuecomment-573817901>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ALSX5R4GCDCJIQRD745JHKTQ5S26DANCNFSM4KBNYWXQ>.