Re: grib2 fie read

Hi Dave,

Thanks for your email and help! I was wondering if there is a way to read theses GRIB2 files correctly. I think these GRIB2 files may not be in error.

Thanks much,

CL

----- Original Message -----

From: "David Brown" <dbrown@ucar.edu>
To: "Chao Luo" <chao.luo@eas.gatech.edu>
Cc: "ncl-talk" <ncl-talk@ucar.edu>
Sent: Monday, September 24, 2012 5:54:35 PM
Subject: Re: grib2 fie read

HI LC,
The warning message has nothing to do with the problem you encountered with out-of-range coordinate values. The message simply means that NCL cannot find a table entry for the variable. In this case that is because there is no published entry for parameter 3 in table 4.2.2.4. The GRIB file is either in error or is using an unpublished parameter value. I do think there may have been an earlier version of this table that had indexes 1,2, and 3 instead of 0, 1, and 2.

Regarding the out-of-range coordinate values, that turns out to be a bug in NCL's generation of lambert conformal coordinates. This file has the Y coordinates going from north to south, which is rather unusual (for lambert conformal grids at least). Anyway, the problem has now been fixed. The new code will be available in NCL 6.1.0.
-dave

On Sep 21, 2012, at 2:42 PM, Luo, Chao wrote:

Hi,

I am reading biomass burning area of NOAA satellite grib2 data by using ncl-6.1.0. I print out the latitude of the grib2, and found maximum of latitude is 1.e+12, which is wrong. The error message when I reading the file is:

warning: Entry (3) not found in code table file /data11/cluo/GAfire/ncl-
6.1.0/lib/ncarg/grib2_codetables/ncep/4/4.2.2.4.table

I was wondering if this the problem caused by this warning. The NCL script I used is very simple:

begin

f = addfile("../NOAA_HMS/march_april/grib2/burned_area_20120316_18_23_12km.grib2","r")
lat = f->gridlat_0(:,:)
lon = f->gridlon_0(:,:)
area = f->VAR_2_4_3_P31_GLC0(:,:)
printMinMax (lat, True)
printVarSummary (lat)
end
~
and output is :

Variable: lat
Type: float
Total Size: 2987436 bytes
746859 values
Number of Dimensions: 2
Dimensions and sizes: [ygrid_0 | 723] x [xgrid_0 | 1033]
Coordinates:
Number Of Attributes: 11
corners : ( 45.7454, 40.18576, 1e+12, 1e+12 )
long_name : latitude
grid_type : Lambert Conformal (secant, tangent, conical or bipolar)
units : degrees_north
Latin2 : 60
Latin1 : 20
Dy : 12
Dx : 12
Lov : 264
Lo1 : 161.7229
La1 : 45.7454
(0)
(0) latitude: min=36.144 max=1e+12

Thanks very much,

CL _______________________________________________
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Received on Mon Sep 24 22:06:43 2012