[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Fwd: Re: [netcdf-java] announce: stable release netcdf-java 4.0]

Hi Robb,
pretty strange. But wgrib2 definitely shows data up there, and the data make perfect sense, because they are totally consistent with the (40km) grib(1) files. I'm generating soundings from the wind, VPTMP, and RH data--and the soundings look totally normal and consistent. 

You can try a new file at http://ruc.noaa.gov/0908221000000.grib2

running
wgrib2 -var -lev -lon -104.660004 39.830002 <filename>
shows good data above lon/lat = -104.66/39.83 all the way up to the top.
I'm afraid I don't know the internals of the grib formats, but I can use wgrib2 per its instructions. I do notice that VPTMP does seem to be rounded off to the nearest degree starting at level 25. But VPTMP varies with lat/lon up there, so it isn't a constant field. 

-Bill

On 3/23/2009 3:57 PM, Robb Kambic wrote:

On Mon, 23 Mar 2009, Bill Moninger wrote:


Hi Robb,
yes, the netcdf4-java code seems to be consistent in reporting fill values in the upper hybrid levels. But wgrib2 reports real data up there. 

-Bill

Here's the output from
-----------------------------------------------------------

wgrib2 -var -lev -lon -105 40 ruc_sample.grib2 |grep VPTMT

101:6841742:VPTMP:1 hybrid level:lon=254.88,lat=40.0639,val=297.03
102:6897701:VPTMP:2 hybrid level:lon=254.88,lat=40.0639,val=298.76
103:6951440:VPTMP:3 hybrid level:lon=254.88,lat=40.0639,val=300.13
104:7003829:VPTMP:4 hybrid level:lon=254.88,lat=40.0639,val=300.3
105:7054644:VPTMP:5 hybrid level:lon=254.88,lat=40.0639,val=301.78
106:7104212:VPTMP:6 hybrid level:lon=254.88,lat=40.0639,val=303.21
107:7153410:VPTMP:7 hybrid level:lon=254.88,lat=40.0639,val=304.33
108:7202486:VPTMP:8 hybrid level:lon=254.88,lat=40.0639,val=305.15
109:7251048:VPTMP:9 hybrid level:lon=254.88,lat=40.0639,val=305.8
110:7297830:VPTMP:10 hybrid level:lon=254.88,lat=40.0639,val=306.3
111:7343669:VPTMP:11 hybrid level:lon=254.88,lat=40.0639,val=306.66
112:7388633:VPTMP:12 hybrid level:lon=254.88,lat=40.0639,val=306.9
113:7431303:VPTMP:13 hybrid level:lon=254.88,lat=40.0639,val=307.12
114:7470554:VPTMP:14 hybrid level:lon=254.88,lat=40.0639,val=307.23
115:7506808:VPTMP:15 hybrid level:lon=254.88,lat=40.0639,val=307.32
116:7540913:VPTMP:16 hybrid level:lon=254.88,lat=40.0639,val=307.34
117:7573226:VPTMP:17 hybrid level:lon=254.88,lat=40.0639,val=307.39
118:7603011:VPTMP:18 hybrid level:lon=254.88,lat=40.0639,val=307.39
119:7631630:VPTMP:19 hybrid level:lon=254.88,lat=40.0639,val=307.51
120:7658113:VPTMP:20 hybrid level:lon=254.88,lat=40.0639,val=307.51
121:7683603:VPTMP:21 hybrid level:lon=254.88,lat=40.0639,val=307.67
122:7707088:VPTMP:22 hybrid level:lon=254.88,lat=40.0639,val=307.67
123:7729290:VPTMP:23 hybrid level:lon=254.88,lat=40.0639,val=307.99
124:7750109:VPTMP:24 hybrid level:lon=254.88,lat=40.0639,val=308.01
125:7768065:VPTMP:25 hybrid level:lon=254.88,lat=40.0639,val=310
126:7783549:VPTMP:26 hybrid level:lon=254.88,lat=40.0639,val=312
127:7796762:VPTMP:27 hybrid level:lon=254.88,lat=40.0639,val=314
128:7807624:VPTMP:28 hybrid level:lon=254.88,lat=40.0639,val=316
129:7816452:VPTMP:29 hybrid level:lon=254.88,lat=40.0639,val=318
130:7823924:VPTMP:30 hybrid level:lon=254.88,lat=40.0639,val=320
131:7829560:VPTMP:31 hybrid level:lon=254.88,lat=40.0639,val=322
132:7834231:VPTMP:32 hybrid level:lon=254.88,lat=40.0639,val=325
133:7836697:VPTMP:33 hybrid level:lon=254.88,lat=40.0639,val=328
134:7837681:VPTMP:34 hybrid level:lon=254.88,lat=40.0639,val=331
135:7839324:VPTMP:35 hybrid level:lon=254.88,lat=40.0639,val=334
136:7840657:VPTMP:36 hybrid level:lon=254.88,lat=40.0639,val=337
137:7843491:VPTMP:37 hybrid level:lon=254.88,lat=40.0639,val=340
138:7846424:VPTMP:38 hybrid level:lon=254.88,lat=40.0639,val=343
139:7848140:VPTMP:39 hybrid level:lon=254.88,lat=40.0639,val=346
140:7849384:VPTMP:40 hybrid level:lon=254.88,lat=40.0639,val=349
141:7850100:VPTMP:41 hybrid level:lon=254.88,lat=40.0639,val=352
142:7850835:VPTMP:42 hybrid level:lon=254.88,lat=40.0639,val=355
143:7851025:VPTMP:43 hybrid level:lon=254.88,lat=40.0639,val=359
144:7851215:VPTMP:44 hybrid level:lon=254.88,lat=40.0639,val=365





145:7851405:VPTMP:45 hybrid level:lon=254.88,lat=40.0639,val=372


Bill,

For vptmp hybrid 45
i did some detail debugging for the actual data read. Data section 7 is only 5 bytes long. The reference value is 372, maybe that's what you are seeing. 
the data template is 40, that's jpeg decoding.
the number of bits is 0, which means all the data values are the same.
This is the code that we use for all jpeg decoding, so I have confidence it's correct. Are you certain that you are request the correct information with wgrib2? Can you come up with another sample? 

Robb...



146:7851595:VPTMP:46 hybrid level:lon=254.88,lat=40.0639,val=385
147:7851785:VPTMP:47 hybrid level:lon=254.88,lat=40.0639,val=400
148:7851975:VPTMP:48 hybrid level:lon=254.88,lat=40.0639,val=422
149:7852165:VPTMP:49 hybrid level:lon=254.88,lat=40.0639,val=450
150:7852355:VPTMP:50 hybrid level:lon=254.88,lat=40.0639,val=500
------------------------------------------------------------------

On 3/20/2009 4:33 PM, Robb Kambic wrote:

On Fri, 20 Mar 2009, Bill Moninger wrote:


Hi Robb,

Thanks for this. The new netcdf4-java works nearly perfectly.
Unfortunately, for one of the variables I'm trying to read out of the file, upper levels are filled with fill-values. Its odd, but I've written a bare-bones simple program to read the variable, and I'm getting nothing but fill values above hybrid level 41 for variable "VPTMP", also known as Virtual_potential_temperature in netCDF-land. 


Bill,
i display the ruc_sample.grig2 in toolsUI, hybrid levels ~42 to 50 had fill values. i even dumped Virtual_potential_temperature hybrid level using the low level reader Grib2GetData it had all fill values. 

this was for hybrid level 45

Grib2GetData C:\data\grib\ruc_sample.grib2 7851442 7851523
If you look at the java docs on the home page it has routines Grib2Dump, Grib2Indexer, ShowGrib, etc that lets one inspect low level values. 

RObb...




The grib2 file is at http://ruc.noaa.gov/ruc_sample.grib2

The relevant part of the code that reads it below.

   ncfile = NetcdfFile.open(filename);
   Debug.println("ncfile is "+ncfile);
   //Debug.println(""+ncfile.getDetailInfo());
   Array data4D;
   Variable v = null;
   Attribute a = null;

   // get grid parameters for most variables
   Dimension d = ncfile.findDimension("hybrid");
   if(d == null) {
     Debug.println("Bad dimension for hybrid");
     System.exit(1);
   }
   tuv_levels = d.getLength();

   // get variables
   int[] origin = new int[] {0, 0, 112,121};
   int[] tuv_size = new int[] {1, tuv_levels, 1,1};
   v  = ncfile.findVariable("Virtual_potential_temperature");
   data4D = v.read(origin, tuv_size);
   Tvar = (double[])data4D.reduce().get1DJavaArray(double.class);
...
 for(int i=0;i<tuv_levels;i++) {
   Debug.println("i: "+i+" t "+Tvar[i]);
 }
This seems pretty obscure, inasmuch as it doesn't effect other variables like pressure, but I fail to find any problem in my code, even after simplifying it down to bare bones.
wgrib2 shows data in all the levels for the specific column specified above. 

I'd appreciate whatever help you can provide.

-Bill

On 3/19/2009 1:12 PM, Robb Kambic wrote:

On Thu, 19 Mar 2009, Bill Moninger wrote:


Hi Robb,
any update on this? Is a new version of netcdf4-java available that will read the grib2 RUC format with its hybrid coordinates? 



The netcdf4-java with the hybrid level fixes are available at:

http://www.unidata.ucar.edu/software/netcdf-java/

let me know if you find any problems.

Robb...

Robb Kambic                       Unidata Program Center
Software Engineer III Univ. Corp for Atmospheric Research 
address@hidden           WWW: http://www.unidata.ucar.edu/
=============================================================================== 



--
William R. Moninger         http://www-frd.fsl.noaa.gov/~moninger/
NOAA / Earth Systems Research Laboratory / Global Systems Division
325 Broadway, R/GSD1                           voice: 303-497-6435
Boulder, CO 80305                              fax:   303-497-3329
=============================================================================== Robb Kambic Unidata Program Center 
Software Engineer III               Univ. Corp for Atmospheric Research
address@hidden           WWW: http://www.unidata.ucar.edu/
=============================================================================== 


--
William R. Moninger         http://www-frd.fsl.noaa.gov/~moninger/
NOAA / Earth Systems Research Laboratory / Global Systems Division
325 Broadway, R/GSD1                           voice: 303-497-6435
Boulder, CO 80305                              fax:   303-497-3329
=============================================================================== 
Robb Kambic                       Unidata Program Center
Software Engineer III               Univ. Corp for Atmospheric Research
address@hidden           WWW: http://www.unidata.ucar.edu/
=============================================================================== 

--
William R. Moninger         http://www-frd.fsl.noaa.gov/~moninger/
NOAA / Earth Systems Research Laboratory / Global Systems Division
325 Broadway, R/GSD1                           voice: 303-497-6435
Boulder, CO 80305                              fax:   303-497-3329