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[GEMPAK #OFK-421943]: problems with gdgrib



Kathrin,

The parameter order to the CAPE and CINS functions is:
CAPE ( PRES, HGHT, TMPC, DWPC )                                 
CINS ( PRES, HGHT, TMPC, DWPC )                                 

You cannot switch the order of PRES and HGHT. When you do as below, the 
stability is being
computed from the incorrect grid values.

When you compute a function in GEMPAK, a default name for the function is 
created
if you do not supply one. The default name is a combination of the function and
parameter passed (truncated to 8 letters generally). You can specify that
you want the grid to be called "CAPE" in the output file by setting GRDNAM=CAPE.

Also, the GLEVEL and GDATTIM parameters can be overridden. By default, your
input below will define that CAPE output grid as 100MB, but you could define it 
to
be a "surface" CAPE by using:
GRDNAM=cape@0%none

You can always overwrite the PDS grid parameter number in GDGRIB for output 
should that be necessary.
As for output to another format, you can use the GEMPAK library to create your 
own 
conversion program. Generally, the best starting point is to take a program 
that does what you want, and then modify it. For example, the GDDIAG program 
would coimpute a parameter, you would then replace the call to write the GEMPAK 
forat grid with the api to the data format you were needing.

Steve Chiswell
Unidata User Support


> Hello,
> 
> I want to calculate cape with gddiag and then to convert my calculated cape to
> grib.
> Calculating cape works fine with gddiag:
> GEMPAK-GDDIAG>d
> GDFILE    Grid file
> era40_pl00_6h_3param_13level_1992113018.grd
> GDOUTF    Output grid file                  capetest.grd
> GFUNC     Scalar grid                       cape(pres,hght,tmpc,dwpc)
> GDATTIM   Grid date/time                    last
> GLEVEL    Grid level                        1000
> GVCORD    Grid vertical coordinate          pres
> GRDNAM    Grid parameter name
> GRDTYP    Diagnostic grid type (Scalar/Vec  S
> GPACK     Packing type/number of bits
> GRDHDR    Grid Header Flags
> PROJ      Map projection/angles/margins|dr  ced/0;0;0
> GRDAREA   Area covered by grid              -90;-180;90;180
> KXKY      Number of grid points in x;y      320;160
> MAXGRD    Maximum number of grids           10000
> CPYFIL    Grid file whose navigation is to
> ANLYSS    Grid analysis block
> GEMPAK-GDDIAG>r
> 
> 
> TIME1             TIME2         LEVL1 LEVL2   VCORD PARM
> 921130/1800F000                      1000          PRES CAPEPRES
> Enter a new grid parameter name, <cr> to accept or type EXIT:
> Parameters requested: GDFILE,GDOUTF,GFUNC,GDATTIM,GLEVEL,GVCORD,GRDNAM,
> GRDTYP,GPACK,GRDHDR,PROJ,GRDAREA,KXKY,MAXGRD,CPYFIL,ANLYSS.
> GEMPAK-GDDIAG>
> 
> I'm able to plot my calculated cape with gdcntr:
> GEMPAK-GDCNTR>d
> GDATTIM   Grid date/time                    last
> GLEVEL    Grid level                        1000
> GVCORD    Grid vertical coordinate          pres
> GFUNC     Scalar grid                       capepres
> GDFILE    Grid file                         capetest.grd
> CINT      Contour interval/min/max          0
> LINE      Color/type/width/label/smth/fltr  9
> MAP       Map color/dash/width/filter flag  25
> MSCALE    fgc;bgc;mask/units/lat;hide/valu  0
> TITLE     Title color/line/title            1
> DEVICE    Device|name|x size;y size|color   xw
> SATFIL    Satellite image filename(s)
> RADFIL    Radar image filename(s)
> IMCBAR    Color/ornt/anch/x;y/ln;wd/freq
> PROJ      Map projection/angles/margins|dr  ced/0;0;0
> GAREA     Graphics area                     -90;-180;90;180
> IJSKIP    Iskp;Istrt;Istp/Jskp;Jstrt;Jstp
> CLEAR     Clear screen flag                 YES
> PANEL     Panel loc/color/dash/width/regn   0
> TEXT      Size/fnt/wdth/brdr/N-rot/just/hw  1
> SCALE     Scalar scale / vector scale       999
> LATLON    Line color/dash/width/freq/inc/l
> HILO      Color/symbol/rng/rad/cnt/intp
> HLSYM     HILO txt size/posn/font/wdth/hw
> CLRBAR    Color/ornt/anch/x;y/ln;wd/freq|t
> CONTUR    Subbox/smooth                     0
> SKIP      Skip_cntr/skip_plt_x;skip_plt_y   0
> FINT      Fill interval/min/max             0
> FLINE     Fill colors/fill types            10-20
> CTYPE     Contour type:  C/F                C
> LUTFIL    Enhancement lookup table filenam
> STNPLT    Txtc/txt attr|marker attr|stnfil
> GEMPAK-GDCNTR>r
> Creating process: xw for queue 524292
> 
> Grid file: capetest.grd
> GRID IDENTIFIER:
> TIME1             TIME2         LEVL1 LEVL2   VCORD PARM
> 921130/1800F000                      1000          PRES CAPEPRES
> 
> GAREA:     -90;-180;90;180              SCALE:  0
> 
> MINIMUM AND MAXIMUM VALUES     0.00  6698.75
> 
> LINE CONTOURS:
> 
> LEVELS:         0.00   700.00  1400.00  2100.00  2800.00  3500.00  4200.00
> 
> LEVELS:      4900.00  5600.00  6300.00
> Enter <cr> to accept parameters or type EXIT:
> Parameters requested: GDATTIM,GLEVEL,GVCORD,GFUNC,GDFILE,CINT,LINE,MAP,
> MSCALE,TITLE,DEVICE,SATFIL,RADFIL,IMCBAR,PROJ,GAREA,IJSKIP,CLEAR,PANEL,TEXT,
> SCALE,LATLON,HILO,HLSYM,CLRBAR,CONTUR,SKIP,FINT,FLINE,CTYPE,LUTFIL,STNPLT.
> GEMPAK-GDCNTR>
> 
> But why is my calculated cape called capepres? And why does gddiag calculates
> something completely different if I type:
> gfunc=cape(hght,pres,tmpc,dwpc) ?
> capehght has different values than capepres.
> 
> But my main problem is converting my calculated capepres to grib with gdgrib:
> GEMPAK-GDGRIB>d
> GDFILE    Grid file                         capetest.grd
> GFUNC     Scalar grid                       capepres
> GDATTIM   Grid date/time                    last
> GLEVEL    Grid level                        1000
> GVCORD    Grid vertical coordinate          pres
> GBTBLS    Input GRIB decoding tables
> GBFILE    GRIB data file name               capetest.grb
> VERCEN    PDS byte_4/byte_5/byte_6/byte_26
> PDSVAL    GRIB PDS grid identifier overrid
> PRECSN    Packing precision
> WMOHDR    WMO_ID/Origin_ID/DDHHMM
> CPYFIL    Grid file whose navigation is to
> PROJ      Map projection/angles/margins|dr  ced/0;0;0
> GRDAREA   Area covered by grid              -90;-180;90;180
> KXKY      Number of grid points in x;y      320;160
> GEMPAK-GDGRIB>r
> WARNING -- Default precision D/5 used.
> [GDGRIB 4]  Warning:  grid not found in grdnav.tbl...continuing.
> [GDGRIB -83]  Cannot find parameter in tables.
> Parameters requested: GDFILE,GFUNC,GDATTIM,GLEVEL,GVCORD,GBTBLS,GBFILE,
> VERCEN,PDSVAL,PRECSN,WMOHDR,CPYFIL,PROJ,GRDAREA,KXKY.
> GEMPAK-GDGRIB>
> 
> Does a table exist which recognizes capepres as cape?
> Is it possible to convert .grd into a different format than grib or grib2?
> 
> Any help would be appreciated.
> 
> Kathrin
> 
> 
> 
> 
> 


Ticket Details
===================
Ticket ID: OFK-421943
Department: Support GEMPAK
Priority: Normal
Status: Closed