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19990929: ECMWF data

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  • Subject: 19990929: ECMWF data
  • Date: Wed, 29 Sep 1999 15:28:10 -0600
Brett,

You will see below that your Grid ID is defined as #255, and not
one of the known tile sectors 1 - 12 for the ecmwf grid IDs
that are used for the grids in the IDD.

The problem here is that by using a grid ID of 255, the GDS is used to
define the map projection- ie, it is not known ahead of time.
The GDS does not give you any information that the grid sector
is part of a larger grid area, and you cannot be guaranteed that
the next grid #255 is part of the same larger grid.

It would be possible to hard code in the values for this case in the
bd_gem_grid.f file and have the grid 255 define a 1.5x1.5 global grid-
but it would break if any ECMWF grid #255 was not part of the grid. For 
instance, 
the ECMWF defines a thinned grid as #255.


Steve Chiswell
Unidata User Support



>From: Brett Newkirk <address@hidden>
>Organization: .
>Keywords: 199909291858.MAA24041

>Hi Steve:
>I have 2 attachments below: TILE and TILE_NAGRIB. TILE has just some
>contents from a program gribdump which outputs GRIB header information-it 
>has data from two separate files, the same variable, different tiles.
>TILE_NAGRIB has the data from tile C. If this data is not one of the ECMWF
>data already known, what data must I provide in regards to this data?
>****************
>TILE:
>-----------------------------------------------------
>                     Header : 1
>         Originating Center : 98 (European Center for Medium-Range Weather
>Forecasts - Reading)
>                    Process : 193 (ECMWF model 193)
>                       Grid : 255
>             points in grid : 3660
>                  Parameter : 2 (P_msl)
>                      Units : Pa
>                 Level Type : Mean Sea
>             Reference Time : 1999/09/28:12:00
>                  Time Unit : Hour
>       Time Range Indicator : Reference Time + P1
>                Time 1 (P1) : 12
>       Decimal Scale Factor : 0
>        Binary Scale Factor : 0
>            Reference Value : 99289.937500
>              Minimum Value : 99289.94
>             Number of Bits : 12
>               BMS Included : FALSE
>               GDS Included : TRUE
>        IsInternationalGrid : FALSE
>               GRIB Edition : 1
>        Parameter Table Ver : 128
>    GDS representation type : 0 (Latitude/Longitude)
>          Number of columns : 60
>             Number of rows : 61
>           Number of points : 3660
>               Kind of grid : rectangular
>          GDS res/comp flag : 0x80
>         GDS scan mode flag : 0
>    GDS no. of vert. coords : 0
>                     GDS Ni : 60
>                     GDS Nj : 61
>                    GDS La1 : 90.000000
>                    GDS Lo1 : 136.500000
>                    GDS La2 : 0.000000
>                    GDS Lo2 : -135.000000
>                     GDS Di : 1.500000
>                     GDS Dj : 1.500000
>-----------------------------------------------------
>                     Header : 1
>         Originating Center : 98 (European Center for Medium-Range Weather
>Forecasts - Reading)
>                    Process : 193 (ECMWF model 193)
>                       Grid : 255
>             points in grid : 3660
>                  Parameter : 2 (P_msl)
>                      Units : Pa
>                 Level Type : Mean Sea
>             Reference Time : 1999/09/28:12:00
>                  Time Unit : Hour
>       Time Range Indicator : Reference Time + P1
>                Time 1 (P1) : 0
>       Decimal Scale Factor : 0
>        Binary Scale Factor : 1
>            Reference Value : 97862.687500
>              Minimum Value : 97862.69
>             Number of Bits : 12
>               BMS Included : FALSE
>               GDS Included : TRUE
>        IsInternationalGrid : FALSE
>               GRIB Edition : 1
>        Parameter Table Ver : 128
>    GDS representation type : 0 (Latitude/Longitude)
>          Number of columns : 60
>             Number of rows : 61
>           Number of points : 3660
>               Kind of grid : rectangular
>          GDS res/comp flag : 0x80
>         GDS scan mode flag : 0
>    GDS no. of vert. coords : 0
>                     GDS Ni : 60
>                     GDS Nj : 61
>                    GDS La1 : 90.000000
>                    GDS Lo1 : -133.500000
>                    GDS La2 : 0.000000
>                    GDS Lo2 : -45.000000
>                     GDS Di : 1.500000
>                     GDS Dj : 1.500000
>**********
>TILE_NAGRIB
> 
> IDS bytes 0 -  4 (GRIB msg id)    = GRIB
> IDS bytes 5 -  7 (ids.msg_length) = 5574
> IDS byte       8 (ids.edition)    = 1
> PDS bytes  1- 3 (pds.length)      = 28
> PDS byte      4 (pds.version)     = 128
> PDS byte      5 (pds.center)      = 98
> PDS byte      6 (pds.process)     = 193
> PDS byte      7 (pds.grid_id)     = 255
> PDS byte      8 (pds.flag)        = 128
> PDS byte      9 (pds.parameter)   = 151
> PDS byte     10 (pds.vcoord)      = 102
> PDS bytes    11 (pds.level_1)     = 0
> PDS bytes    12 (pds.level_2)     = 0
> PDS bytes 11-12 (pds.level)       = 0
> PDS byte     13 (pds.year)        = 99
> PDS byte     14 (pds.month)       = 9
> PDS byte     15 (pds.day)         = 28
> PDS byte     16 (pds.hour)        = 12
> PDS byte     17 (pds.minute)      = 0
> PDS byte     18 (pds.time_unit)   = 1
> PDS byte     19 (pds.time_p1)     = 12
> PDS byte     20 (pds.time_p2)     = 0
> PDS byte     21 (pds.time_range)  = 0
> PDS bytes 22-23 (pds.avg_num)     = 0
> PDS byte     24 (pds.avg_miss)    = 0
> PDS byte     25 (pds.century)     = 20
> PDS byte     26 (pds.izero)       = 0
> PDS bytes 27-28 (pds.dec_scale)   = 0
> PDS EXT FLAG (1-app,0-nc,-1-rep)  = 0
> PDS EXT STRING                    = 
> GDS bytes  1 -  3 (gds.length)    = 32
> GDS byte        4 (gds.NV)        = 0
> GDS byte        5 (gds.PV)        = 255
> GDS byte        6 (gds.grid_proj) = 0
> GDS bytes  7 -  8 (Nx)            = 60
> GDS bytes  9 - 10 (Ny)            = 61
> GDS bytes 11 - 13 (La1)           = 90000
> GDS bytes 14 - 16 (Lo1)           = 136500
> GDS byte       17 (flag)          = 128
> GDS bytes 18 - 20 (La2)           = 0
> GDS bytes 21 - 23 (Lo2)           = -135000
> GDS bytes 24 - 25 (skipped)
> GDS bytes 26 - 27 (skipped)
> GDS byte       28 (mode)          = 0
> GDS bytes 29 - 32 (skipped)
> GDS bytes 33 - 35 (skipped)
> GDS bytes 36 - 38 (skipped)
> GDS byte       39 (skipped)
> GDS bytes 40 - 42 (skipped)
> GDS bytes 43 - 45 (skipped)
> GDS bytes 46 - 48 (skipped)
> GDS byte       49 (skipped)
> GDS bytes 50 - 52 (skipped)
>
> MESG# NMCGRD# PRM#   VCD#    GEMPAK_TIME       LEVL1 LEVL2  VCRD PARM 
>    1   255    151    102    990928/1200F012        0        NONE PMSL        
>
>
>         1 GRIB messages were read or scanned from the GRIB file:
>     E00PC098E.grb                                                          
>
> Parameters requested:
>GBFILE,INDXFL,GDOUTF,PROJ,GRDAREA,KXKY,MAXGRD,CPYFIL,
> GAREA,OUTPUT,GBTBLS,GBDIAG.
>
>*************
>Thanks again-------Brett
>
>
>Brett Newkirk    E-MAIL: address@hidden
>Office: ATG 424  Atmospheric Science/Geophysics Building
>Mailing Address: Department of Atmospheric Sciences, University of Washington
>                 Box 351640
>                 Seattle, WA 98195-1640
>Office Phone: (206) 685-2183
>
>