BUFR in Grads

Mark Northcroft mark at CRG.BPB.WITS.AC.ZA
Thu Jan 31 05:50:28 EST 2008


Hi all,

I am new to this list, and hope someone may be able to offer some help.
This is my first attempt at processing BUFR files, and am having
difficulty coming to grips with it.

I am trying to process EUMETSAT Global Instability Index data in BUFR
format using Grads.  There doesnt seem to be all that much help on the
web, and I am quite getting quite confused with the format and placement
of the BUFR Table B, as well as the structure of the control file.

Firstly the control file...
Currently, my control looks like this :

dset ^test.bfr
title "GII data"
undef 1e+20
dtype bufr
XVAR 5,31
YVAR 6,31
TVAR yr 4,1 mo 4,2 dy 4,3 hr 4,4 mn 4,5 sc 4,6
STID 2,020
TDEF 1 LINEAR 18Z4mar2007 15mn
vars 8
giilon 0 6,1 Longitude
giilat 0 5,1 Latitude
satzenith 0 7,24 Satellite Zenith
ki 0 13,044 K Index
ko 0 13,045 KO Index
li 0 13,042 Lifted Index
maxb 0 12,046 Max Bouyancy
pw 0 13, 016 Precipitable water
endvars

A q file - returns the following:

Descriptor: ../gii/gii.ctl
  Binary: ../gii/test.bfr
  Type = BUFR Station Data
  Tsize = 1
  Number of Variables = 8
    giilon 0 6 Longitude                              <---------------
The lack of the ,1 defining the longitude code worries me.  Is the file
being read as a BUFR file?
    giilat 0 5 Latitude                                 <---------------
    satzenith 0 7 Satellite Zenith
    ki 0 13 K Index
    ko 0 13 KO Index
    li 0 13 Lifted Index
    maxb 0 12 Max Bouyancy
    pw 0 13 Precipitable water

Secondly,  I am trying to find the correct format and location to save
Table B to so Grads can access it.  (I am assuming it is in
/usr/local/lib/grads/tables/ so I have placed it there) .  The
descriptor file loads with:

Scanning description file:  ../gii/gii.ctl
Data file ../gii/test.bfr is open as file 1
LON set to 0 360
LAT set to -90 90
LEV set to 500 500
Time values set: 2007:3:4:18 2007:3:4:18

However I get the following error message when attempting to display a
variable:

Parsing BUFR file ../gii/test.bfr
Error opening table B file (/usr/local/lib/grads/tables/B3M-000-012-B):
No such file or directory
Error from getbufr: gabufr_open failed
Data Request Error:  Variable is 'pw'
  Error ocurred at column 1
DISPLAY error:  Invalid expression
  Expression = pw

I am sure I am missing something relatively obvious (like the format of
Table B, as well as a naming convention or something) but I keep going
round in circles.
I am holding thumbs that someone may help, or at least point me in the
direction of a helpful wiki!

Thanks all!

Mark



--
___________________________________
Mark Northcroft

Climatology Research Group
Room 101A
Bernard Price Building
East Campus
University of the Witwatersrand

P.Bag 3
Wits
2050

Tel:        +27 11 717 6531
Fax:       +27 11 717 6535

Mail: mark at crg.wits.ac.za
        marknorthcroft at gmail.com

___________________________________



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