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19990106: cloud ceiling...

>From: Maureen Ballard <address@hidden>
>Organization: UK Ag Weather Center
>Keywords: 199901062040.NAA27227

>Steve,
>
>Looking over some archived messages, I came across one concerning cloud
>ceilings. At that time (back in 95) there was no GEMPAK parameter for
>cloud ceiling. I also have not found mention of one in the manual help
>pages. Has one been created or in the plans? We are interested in
>plotting these values on a map. If a parameter for cloud ceiling is not
>planned I guess I'll start figuring out a way to calculate it from the
>cloud groups.
>
>Any help would be greatly appreciated.
>
>Thanks!
>
>Maureen
>

Maureen,
At the end of this message, you will find the source for a routine I 
created $GEMPAKHOME/src/gemlib/pr/prceil.f

Place the routine in the above mentioned directory, and add the
(tab)   $(ALIB)/(prceil.o) \
target to the makefile in that directory, and just as you did for
the soil moisutre routine, add the appropriate invocation to
the $GEMPAKHOME/src/gemlib/pc/pcfunc.f routine:

C*
          ELSE IF ( fff .eq. 'PR_CMBC' ) THEN
            data ( iout (i) ) = PR_CMBC ( d1, d2, d3)
C*
          ELSE IF ( fff .eq. 'PR_CEIL' ) THEN            <--- add these 2 lines
            data ( iout (i) ) = PR_CEIL ( d1, d2, d3)    <--/
C*
          ELSE IF ( fff .eq. 'PR_RWSH' ) THEN
            data ( iout (i) ) = PR_RWSH ( d1 )

Compile these two routines
cd $GEMPAKHOME/src/gemlib/pr
make clean
make
make clean
cd $GEMPAKHOME/src/gemlib/pc
make clean
make
make clean

Next, add some variables to the $GEMTBL/parms/pcconv.tbl to the
end of the cloud parameter section, eg:
<clip>
CSYM = PR_CSYM ( CTYM )
CSYH = PR_CSYH ( CTYH )
CSYT = PR_CSYT ( CTYL, CTYM, CTYH )
CEIL = PR_CEIL ( CHC1, CHC2, CHC3 ) <--- add these three lines
CEIO = PT_CMCL ( CEIL )             <--/
CEIH = PR_CLHX ( CEIL )             <--/

Now, just recompile the surface programs like sflist, sfmap etc
cd $GEMPAKHOME/src/programs/sf
make clean
make all
make install
make clean


The ceiling routine will chose the lowest level with at least broken
cloud cover (broken, overcast, obscured).
CEIL is similar to the COMT variable, giving the combined cloud height*10 + 
coverage.
CEIO is similar to CLDT giving the old SA abbreviation form, and CEIH
will return just the height (in 100s of feet) like CLHx.

For example:
 PARM = CHC1;CHC2;CHC3;CEIL;CEIO;CEIH                                           
 

    STN  YYMMDD/HHMM      CHC1     CHC2     CHC3     CEIL     CEIO     CEIH
    BWG    990106/1200    202.00   244.00 -9999.00   244.00      24O    24.00
    CVG    990106/1200    324.00 -9999.00 -9999.00   324.00      32O    32.00
    FFT    990106/1200    262.00   394.00 -9999.00   394.00      39O    39.00
    FTK    990106/1200    224.00 -9999.00 -9999.00   224.00      22O    22.00
    HOP    990106/1200    152.00   304.00 -9999.00   304.00      30O    30.00
    JKL    990106/1200    284.00 -9999.00 -9999.00   284.00      28O    28.00
    LEX    990106/1200    302.00   553.00   704.00   553.00      55B    55.00
    LOU    990106/1200    264.00 -9999.00 -9999.00   264.00      26O    26.00
    LOZ    990106/1200    183.00   333.00   604.00   183.00      18B    18.00
    OWB    990106/1200    184.00 -9999.00 -9999.00   184.00      18O    18.00
    PAH    990106/1200    304.00 -9999.00 -9999.00   304.00      30O    30.00
    SDF    990106/1200    264.00 -9999.00 -9999.00   264.00      26O    26.00
    SME    990106/1200    212.00   304.00 -9999.00   304.00      30O    30.00

Steve Chiswell


<<------------Source for prceil.f----------------->
        REAL FUNCTION PR_CEIL  ( chc1, chc2, chc3 )
C************************************************************************
C* PR_CEIL                                                              *
C*                                                                      *
C* This routine determines the height of the cloud ceiling. The ceiling *
C* is the lowest level with at least Broken Cloud cover.                *
C*                                                                      *
C* PR_CEIL  ( CHC1, CHC2, CHC3 )                                        *
C*                                                                      *
C* Input parameters:                                                    *
C*      CHC1, CHC2, CHC3        REAL    Combined cloud height/coverage  *
C*                                                                      *
C* Output parameters:                                                   *
C*      PR_CEIL                 REAL    Ceiling Height                  *
C**                                                                     *
C* Log:                                                                 *
C* Chiz/Unidata          1/99                                           *
C************************************************************************
        INCLUDE         'GEMINC:GEMPRM.PRM'
        REAL            chc1,chc2,chc3
        REAL            height
        INTEGER         ctype
C*
        INCLUDE       'GEMINC:ERMISS.FNC'
C------------------------------------------------------------------------
        PR_CEIL = RMISSD
C
C*      Check for missing data.
C

        if ( .not. ERMISS ( chc1 ) ) then
           height = float(int(chc1) / 10)
           ctype = mod(INT(chc1),10)
           if((ctype.eq.3).or.(ctype.eq.7).or.
     +        (ctype.eq.4).or.(ctype.eq.8).or.
     +        (ctype.eq.5).or.(ctype.eq.9)) then
              PR_CEIL = chc1
              RETURN
           endif
        endif
        if ( .not. ERMISS ( chc2 ) ) then
           height = float(int(chc2) / 10)
           ctype = mod(INT(chc2),10)
           if((ctype.eq.3).or.(ctype.eq.7).or.
     +        (ctype.eq.4).or.(ctype.eq.8).or.
     +        (ctype.eq.5).or.(ctype.eq.9)) then
              PR_CEIL = chc2
              RETURN
           endif
        endif
        if ( .not. ERMISS ( chc3 ) ) then
           height = float(int(chc3) / 10)
           ctype = mod(INT(chc3),10)
           if((ctype.eq.3).or.(ctype.eq.7).or.
     +        (ctype.eq.4).or.(ctype.eq.8).or.
     +        (ctype.eq.5).or.(ctype.eq.9)) then
              PR_CEIL = chc3
              RETURN
           endif
        endif
C*
        RETURN
        END