How to build Vtable?

[rabbanidu93]

Dear altruists,

Can anyone share any detailed documents or ideas in preparing Vtable for any datasets (i.e. ECMWF 10-days new open datasets)? I don't know how to set the values for GRIB2 Discp, GRIB2 Level, Level Code inside Vtable. I got some values from g2print.exe. But I think, it shows some mismatched value for some variables as the datasets are new. Vtable.ECMWF or other ECMWF vtable doesn't work for this datasets. I have attached a sample data & the index file of the data.

Thank you in advance.

 

[kwerner]

Hi,

Typically the g2print.exe should show the information you need. For e.g., if I were to look at a file from GFS, I would see something like this.

      NCEP GFS GDAS/FNL               
---------------------------------------------------------------------------------------
 rec     Prod    Cat     Param   Lvl    Lvl      Lvl        Prod    Name            Time          Fcst
 num   Disc     num    code    one   two     Templ                                                     hour
---------------------------------------------------------------------------------------
   5         0         3          5       100   1000     0           0         HGT      2016-03-23_00:00:00   00         
   6         0         0          0       100   1000     0           0         TMP      2016-03-23_00:00:00   00         
   7         0         1          1       100   1000     0           0          RH       2016-03-23_00:00:00   00         
   8         0         2          2       100   1000     0           0        UGRD    2016-03-23_00:00:00   00         
   9         0         2          3       100   1000     0           0        VGRD     2016-03-23_00:00:00   00         
  10        0         2        10       100   1000     0           0         ABSV     2016-03-23_00:00:00   00         
  11        0        14      192      100   1000     0           0        O3MR     2016-03-23_00:00:00   00         
  12        0         3         5        100   2000     0           0          HGT      2016-03-23_00:00:00   00         
  13        0         0         0        100   2000     0           0          TMP      2016-03-23_00:00:00   00         
  14        0         1         1        100   2000     0           0           RH       2016-03-23_00:00:00   00         
  15        0         2         2        100   2000     0           0       UGRD     2016-03-23_00:00:00   00         
  16        0         2         3        100   2000     0           0        VGRD     2016-03-23_00:00:00   00         
  17        0         2        10       100   2000     0           0        ABSV     2016-03-23_00:00:00   00         
  18        0        14      192      100   2000     0           0       O3MR     2016-03-23_00:00:00   00

and if you look at the Vtable.GFS, you'll see

GRIB1| Level| From |  To      | metgrid  | metgrid | metgrid                                 |GRIB2 |GRIB2 | GRIB2| GRIB2|
Param| Type |Level1|Level2 | Name     | Units     | Description                           |Discp  | Catgy  | Param| Level  |
-----+------+------+------+----------+---------+-----------------------------------------+-----------------------------+
  11     | 100  |   *      |            | TT          | K          | Temperature                           |  0      |  0         |  0        | 100    |
  33     | 100  |   *      |            | UU         | m s-1   | U                                             |  0      |  2         |  2       | 100    |
  34     | 100  |   *      |            | VV          | m s-1   | V                                             |  0      |  2         |  3       | 100     |
  52     | 100  |   *      |            | RH         | %         | Relative Humidity                   |  0      |  1         |  1       | 100     |
   7      | 100  |   *      |            | HGT       | m         | Height                                     |  0      |  3         |  5       | 100     |
  11     | 105  |   2     |            | TT          | K          | Temperature       at 2 m          |  0      |  0         |  0        | 103     |
  52     | 105  |   2     |            | RH         | %         | Relative Humidity at 2 m        |  0      |  1         |  1        | 103    |
  33     | 105  |  10    |            | UU         | m s-1   | U                 at 10 m                |  0      |  2         |  2        | 103    |
  34     | 105  |  10    |            | VV          | m s-1   | V                 at 10 m                |  0      |  2         |  3        | 103     |

So you can see that, for e.g., for HGT at level 100, the grib2 codes (right side of the grib table) are 0, 3, 5, 100.

It's best to start with a Vtable that is already created and just make modifications to it for your new dataset. Unfortunately I'm not able to see the codes from the file you attached. When you use g2print.exe, are you seeing anything similar to what I'm showing you?