why I got 9.999e+20

[Wesley Ebisuzaki]

Jhih,

I made a regional subset with your parameters and found no missing data.
Perhaps
you entered the parameters incorrectly. The wgrib description of the
grid should
look like,

rec 1:0:date 1979110800 HGT kpds5=7 kpds6=1 kpds7=0 levels=(0,0)
grid=255 sfc anl:
HGT=Geopotential height [gpm]
timerange 0 P1 0 P2 0 TimeU 1 nx 47 ny 47 GDS grid 3 num_in_ave 0 missing 0
center 7 subcenter 15 process 140 Table 131 scan: WE:SN winds(grid)
Lambert Conf: Lat1 32.294000 Lon1 -93.877000 Lov -107.000000
Latin1 50.000000 Latin2 50.000000 LatSP 0.000000 LonSP 0.000000
North Pole (47 x 47) Dx 32.463000 Dy 32.463000 scan 64 mode 136
min/max data 0 1063.25 num bits 14 BDS_Ref 0 DecScale 0 BinScale -3

To plot the field using grads, I modified the control file (xdef and
ydef lines) so it
would show the domain in question.

xdef 28 linear -91.5 0.5 <-- new lines
ydef 22 linear 32 0.5

When I used the new control file, 3 of the corners were undefined.
Nothing wrong
because the command to subset the grid looked for all the grid points
<<within>> the
box in question. Make the box bigger if you want to include the corners.

Wesley Ebisuzaki


Shih, Jhih-Shyang wrote:
>
> Dear Experts:
>
> I download NARR grb files and extract following subregion:
>
> Lon: -91.5 (W) -78.0 (E)
>
> Lat: 42.5 (North) 32 (South)
>
> Variables (tmpprs, hgtprs, …) within part of the subregion (within the
> US) have value of 9.999e+20, which means undefined I believe. My
> question is why it is undefined? What is the cause?
>
> Thanks very much.
>
> Jhih-Shyang
>