Update documentation for several UPP files (#696)

* update upp_math to remove warnings

* document members of kinds_mod.F

* document members/return vals for native_endianness.f

* basic documentation of GFIP3.f to remove warnings

* silence warnings for CTLBLK.f

* eliminate warnings for GET_BITS.f

* switch SURFCE.f comments to fortran & silence warnings

* silence warnings for FRZLVL.f and FRZLVL2.f

* silence warnings on SMOOTH.f

* silence warnings on SELECT_CHANNELS.f

* silence warnings on SCLFLD.f

* silence warnings for retrieve_index.f

* silence warnings on PARA_RANGE.f

* silence warnings on GFSPOST.F

* silence warnings on LFMFLD.f

* silence warnings on FILL_PSETFLD.f

* silence warnings on EXCH_c_float.f

* silence warnings on DEWPOINT.f

* update MDL2THANDPV.f

* updates to UPP_MATH.f and MDL2THANDPV.f

* update kinds_mod.F

* update native_endianness.f

* silence warnings on UPP_PHYSICS.f

* update MDL2STD_P.f

* update GET_BITS.f

* supress GFIP3.f warnings; update var defs

* update var defs in GFIP3.f

* update kinds_mod.F

* update kinds_mod.F

* update retrieve_index.f

* update GFIP3.f

* update SMOOTH.f

* update SMOOTH.f

* update native_endianness.f

* silence warnings on LFMFLD_GFS.f; correct copy-paste errors

* update omega in GFSPOST.F

* update omega units in GFSPOST.F

---------

Co-authored-by: gspetro <gillian.s.petro@gmail.com>

sorc/ncep_post.fd/CTLBLK.f

@@ -9,8 +9,8 @@ module CTLBLK_mod
 !  2011-02    Jun Wang  - ADD variables for grib2
 !  2011-12-14 SARAH LU  - ADD AER FILENAME
 !  2011-12-23 SARAH LU  - ADD NBIN FOR DU, SS, OC, BC, SU
-!  2021-09-30 JESSE MENG- 2D DECOMPOSITION
-!  2022-09-22 Li(Kate) Zhang- Add option for NASA GOCART as "nasa_on", add NBIN for NO3 and NH4
+!  2021-09-30 JESSE MENG - 2D DECOMPOSITION
+!  2022-09-22 Li(Kate) Zhang - Add option for NASA GOCART as "nasa_on", add NBIN for NO3 and NH4
 !  2022-11-08 Kai Wang  - Replace aqfcmaq_on with aqf_on
 !  2023-01-24 Sam Trahan - IFI flight levels, runtime of IFI, and record of the bucket time
 !  2023-03-21 Jesse Meng - Add slrutah_on option to use U Utah SLR
@@ -22,10 +22,16 @@ module CTLBLK_mod
   implicit none
 !
   type field_info
+!> ifld @memberof CTLBLK_mod
     integer ifld
+!> lvl @memberof CTLBLK_mod
     integer lvl
+!> lvl1 @memberof CTLBLK_mod
+!> lvl2 @memberof CTLBLK_mod
     integer lvl1,lvl2
+!> ntrange @memberof CTLBLK_mod
     integer ntrange
+!> tinvstat @memberof CTLBLK_mod
     integer tinvstat
   end type
   integer, parameter :: komax=70

sorc/ncep_post.fd/DEWPOINT.f

@@ -41,6 +41,13 @@
 !> 2021-10-31 | J Meng       | 2D Decomposition
 !>
 !> @author Jim Tuccillo W/NP2 @date 1990-05-19
+!--------------------------------------------------------------------------
+!> DEWPOINT() Subroutine that computes dewpoints from vapor pressure.
+!> It computes the dewpoints for the N values of vapor pressure in array VP.
+!>
+!> @param[in] VP Array of N vapor pressures(centibars).
+!> @param[out] TD Dewpoint in degrees absolute.
+!--------------------------------------------------------------------------
       SUBROUTINE DEWPOINT( VP, TD)
 
        use ctlblk_mod, only: jsta, jend, im, spval, ista, iend

sorc/ncep_post.fd/EXCH_c_float.f

@@ -17,6 +17,13 @@
 !> makefile (Tuccillo, personal communication;  Ferrier, Feb '02).
 !>
 !> @author Jim Tuccillo IBM @date 2000-01-06
+!--------------------------------------------------------------------------
+!> EXCH_c_float Subroutines that exchange one halo row.
+!> 
+!> @param[inout] A 
+!> @note As input, A is the array that will have halos exchanged. As output, 
+!> A is the array with halos exchanged.
+!--------------------------------------------------------------------------
       SUBROUTINE EXCH_c_float(A)
 
       use ctlblk_mod, only: num_procs, jend, iup, jsta, idn, mpi_comm_comp, im,&

sorc/ncep_post.fd/FILL_PSETFLD.f

@@ -5,9 +5,8 @@
 !> as parameter name, level type etc from post available field
 !> table.
 !>
-!> @param[in] param_ofld output field.
+!> @param[inout] param_ofld output field.
 !> @param[in] param_afld available field in post.
-!> @param[out] param_ofld output field.
 !>
 !> ### Program History Log
 !> Date | Programmer | Comments
@@ -17,6 +16,15 @@
 !> 2015-03-10 | Lin Gan  | Using flat file data
 !>
 !> @author J. Wang NCEP/EMC @date 2012-01-27
+!-----------------------------------------------------------------------
+!> fill_psetfld() reads post xml control file.
+!> This routine sets the output field GRIB2 information such    
+!> as parameter name, level type etc from post available field
+!> table.
+!>
+!> @param[inout] param_ofld output field.
+!> @param[in] param_afld available field in post.
+!>
       subroutine fill_psetfld(param_ofld,param_afld)
 !
 

sorc/ncep_post.fd/FRZLVL.f

@@ -38,6 +38,13 @@
 !> 2021-10-15 |JESSE MENG    | 2D DECOMPOSITION
 !>
 !> @author Russ Treadon W/NP2 @date 1992-12-22
+!-----------------------------------------------------------------------------
+!> FRZLVL() Subroutine that computes FRZING LVL, Z and RH.
+!> 
+!> @param[out] ZFRZ real Above ground level freezing height.
+!> @param[out] RHFRZ real Relative humidity at freezing level.
+!> @param[out] PFRZL real Pressure at freezing level.
+!>
       SUBROUTINE FRZLVL(ZFRZ,RHFRZ,PFRZL)
 
 !     

sorc/ncep_post.fd/FRZLVL2.f

@@ -43,6 +43,15 @@
 !> 2021-07-28 | W. Meng      | Restrict compuatation from undefined grids
 !>
 !> @author Russ Treadon W/NP2 @date 1992-12-22
+!-------------------------------------------------------------------------------
+!> Subroutine that computes FRZING LVL, Z and RH.
+!>
+!> @param[in] ISOTHERM real Isothermal value of height to be output.
+!> @param[out] ZFRZ real Above ground level/ZFL at isotherm height.
+!> @param[out] RHFRZ real Relative humidity at isotherm level.
+!> @param[out] PFRZL real Pressure at isotherm level.
+!>
+
       SUBROUTINE FRZLVL2(ISOTHERM,ZFRZ,RHFRZ,PFRZL)
 
 !     

sorc/ncep_post.fd/GET_BITS.f

@@ -32,6 +32,20 @@
 !> 1995-04-14 | Baldwin | Modify following Keith Brill's code to use sig digits to compute DEC scale
 !>
 !> @author Iredell W/NP23 @date 1992-10-31
+!-----------------------------------------------------------------------
+!> get_bits() computes number of bits and round field.
+!> 
+!> @param[in] IBM integer bitmap flag (=0 for no bitmap).
+!> @param[in] SGDS real Maximum significant digits to keep.
+!> @param[in] LEN integer Length of the field and bitmap.
+!> @param[in] MG integer (LEN) Bitmap if IBM=1 (0 to skip, 1 tp keep).
+!> @param[in] G real (LEN) Field.
+!> @param[inout] ISCALE integer Decimal scaling.
+!> @param[inout] GROUND real (LEN) Field rounded to decimal scaling.
+!> @param[out] GMIN real Minimum valid rounded field value.
+!> @param[out] GMAX real Maximum valid rounded field value.
+!> @param[inout] NBIT integer Number of bits to pack.
+!>
       SUBROUTINE GET_BITS(IBM,SGDS,LEN,MG,G,ISCALE,GROUND,           &
                           GMIN,GMAX,NBIT)
 
@@ -96,10 +110,10 @@ SUBROUTINE GET_BITS(IBM,SGDS,LEN,MG,G,ISCALE,GROUND,           &
 !>
 !> Note that a fractional number of significant digits is allowed.
 !>
-!> @param[in] AMIN Real Minimum value.
-!> @param[in] AMAX Real Maximum value.
+!> @param[in] RMIN Real Minimum value.
+!> @param[in] RMAX Real Maximum value.
 !> @param[in] RDB Real Maximum # of significant digits OR binary precision if < 0.
-!> @param[out] NBITS Integer Number of bits for packing.
+!> @param[out] NMBTS Integer Number of bits for packing.
 !> @param[out] ISCALE Integer Power of 10 scaling to use.
 !> @param[out] IRET Integer Return code. 0 = normal return.
 !>