LATS4D

[Michael Fiorino]

hi lisa, the reason for different order of the the gauss latitudes is in
the scan mode (2 for lats, and 0 for ncep).  the ncep tradition is N-S
(and you'll get an 'options yrev' in the .ctl calculated from
grib2ctl.pl), but i prefer S-N (the more natural "j" direction).  also,
i purposely limited the precision of the gauss lats in the lats .ctl and
doubt this is an issue for ncl.  the problem may be that ncl is used to
ncep gauss grid (N-S) but lats outputs S-N.  i suspect there's an option
in ncl to tell it the latitudes are ordered N-S...   /r mike

Lisa Murphy wrote:
> Thank you, Mike.
>
> I have just one more question about the grid.
>
> When I type:
>
> wgrib myfile.grb -V
>
> I get:
>
> rec 169:10959648:date 0002120106 HGT kpds5=7 kpds6=100 kpds7=4 levels=(0,4)
> grid=255 4 mb anl:
>   HGT=Geopotential height [gpm]
>   timerange 0 P1 0 P2 0 TimeU 1  nx 128 ny 64 GDS grid 4 num_in_ave 0 missing 0
>   center 7 subcenter 1 process 0 Table 128 scan: WE:NS winds(N/S)
>   gaussian: lat  -87.864000 to 87.864000
>             long 0.000000 to 357.188000 by 2.813000, (128 x 64) scan 2 mode
> 128 bdsgrid 1
>   min/max data 33488.4 33488.4  num bits 64  BDS_Ref 33488.4  DecScale 0
> BinScale -51
>
>
> Is the latitude range correct?  I just ask this because when I've searched
> this wgrib command I always see it in this form (with the northern most
> latitude followed by the southern most latitude):
>
> gaussian: lat  88.542000 to -88.542000
>             long 0.000000 to -1.875000 by 1.875000, (192 x 94) scan 0 bdsgrid 1
>
> I was wondering if this is why I'm getting an error reading the grid in NCL.
>
> Also,
>
> In the control file it says:
> ydef 64 levels
> -87.864 -85.097
> -82.313 -79.526 -76.737 -73.948 -71.158 -68.368 -65.578 -62.787 -59.997 -57.207
> -54.416 -51.626 -48.835 -46.045 -43.254 -40.464 -37.673 -34.883 -32.092 -29.301
> -26.511 -23.720 -20.930 -18.139 -15.348 -12.558  -9.767  -6.977  -4.186  -1.395
>   1.395   4.186   6.977   9.767  12.558  15.348  18.139  20.930  23.720  26.511
>  29.301  32.092  34.883  37.673  40.464  43.254  46.045  48.835  51.626  54.416
>  57.207  59.997  62.787  65.578  68.368  71.158  73.948  76.737  79.526  82.313
>  85.097  87.864
>
> when it should be:
>  lat = -87.8637988392326, -85.0965269883174, -82.3129129478863,
>     -79.5256065726594, -76.7368996803683, -73.9475151539897,
>     -71.1577520115873, -68.3677561083132, -65.5776070108278,
>     -62.7873517989631, -59.9970201084913, -57.2066315276432,
>     -54.4161995260862, -51.6257336749383, -48.8352409662506,
>     -46.0447266311017, -43.2541946653509, -40.463648178115,
>     -37.6730896290453, -34.8825209937735, -32.091943881744,
>     -29.3013596217627, -26.510769325211, -23.7201739335347,
>     -20.9295742544895, -18.1389709902394, -15.3483647594915,
>     -12.5577561152307, -9.76714555919557, -6.97653355394864,
>     -4.18592053318915, -1.3953069108195, 1.3953069108195, 4.18592053318915,
>     6.97653355394864, 9.76714555919557, 12.5577561152307, 15.3483647594915,
>     18.1389709902394, 20.9295742544895, 23.7201739335347, 26.510769325211,
>     29.3013596217627, 32.091943881744, 34.8825209937735, 37.6730896290453,
>     40.463648178115, 43.2541946653509, 46.0447266311017, 48.8352409662506,
>     51.6257336749383, 54.4161995260862, 57.2066315276432, 59.9970201084913,
>     62.7873517989631, 65.5776070108278, 68.3677561083132, 71.1577520115873,
>     73.9475151539897, 76.7368996803683, 79.5256065726594, 82.3129129478863,
>     85.0965269883174, 87.8637988392326 ;
>
>
> I tried bumping up precision from 16 to 64 but it didn't solve this problem.
>
> Thanks again,
> Lisa
>