[gradsusr] Different output values from Grads and wgrib2

[Huddleston, John]

Jennifer

It appears Bo is correct in his analysis for this GRIB2 file. I took Wesley's latest g2ctl and regenerated a new CTL file and IDX file using the latest GrADS-2.0.0 and have the same results. At 30mb GrADS displays temperature data that is much greater than expected. Here is my output. Note at z=24 the temperature range.

ga-> open fnl_20100508_06_00.ctl
Scanning description file:  fnl_20100508_06_00.ctl
Data file fnl_20100508_06_00 is open as file 1
LON set to 0 360
LAT set to -90 90
LEV set to 1000 1000
Time values set: 2010:5:8:6 2010:5:8:6
E set to 1 1
ga-> set z 26
LEV set to 10 10
ga-> d tmpprs
Contouring: 195 to 240 interval 5
ga-> set z 25
LEV set to 20 20
ga-> d tmpprs
Contouring: 195 to 230 interval 5
ga-> set z 24
LEV set to 30 30
ga-> d tmpprs
Contouring: 230 to 310 interval 10
ga-> set z 23
LEV set to 50 50
ga-> d tmpprs
Contouring: 195 to 225 interval 3

John Huddleston

________________________________________
From: gradsusr-bounces at gradsusr.org [gradsusr-bounces at gradsusr.org] On Behalf Of Bo Zhang [bzhang3 at mtu.edu]
Sent: Thursday, October 13, 2011 6:59 PM
To: gradsusr at gradsusr.org
Subject: [gradsusr] Different output values from Grads and wgrib2

Hi great grads users,

I was trying to plot temperature profile with Grads and just found different results from Grads and wgrib2. I am sure that I am reading the same data file. I got the attached profile plot from Grads and the following result from wgrib2 at the same position. One thing should be noticed is that Gtads and wgrib2 number the grid box in different ways. The (0, 0) grid box in Grads (-180:179, -90,90) should be (181,91) in a (0:360, 0,181) system. The bump at 30 mb in the figure exists for any lon-lat position I try, which is wired to me. The other values are also slightly various.

$ ./wgrib2 ***/Grads/fnl_20100508_06_00 -s -ij 181 91 | grep :TMP
3:120296:d=2010050806:TMP:10 mb:anl::val=240.5
8:393851:d=2010050806:TMP:20 mb:anl::val=220.9
13:666758:d=2010050806:TMP:30 mb:anl::val=215.9
18:961202:d=2010050806:TMP:50 mb:anl::val=204.1
23:1271647:d=2010050806:TMP:70 mb:anl::val=193.5
28:1588656:d=2010050806:TMP:100 mb:anl::val=190.7
36:1997953:d=2010050806:TMP:150 mb:anl::val=207.4
43:2356630:d=2010050806:TMP:200 mb:anl::val=223.1
50:2732191:d=2010050806:TMP:250 mb:anl::val=235.9
57:3106953:d=2010050806:TMP:300 mb:anl::val=244.9
64:3498361:d=2010050806:TMP:350 mb:anl::val=254.5
71:3898258:d=2010050806:TMP:400 mb:anl::val=260.8
78:4302495:d=2010050806:TMP:450 mb:anl::val=266.3
85:4751606:d=2010050806:TMP:500 mb:anl::val=270.9
92:5208947:d=2010050806:TMP:550 mb:anl::val=274.5
99:5689297:d=2010050806:TMP:600 mb:anl::val=277.9
106:6172793:d=2010050806:TMP:650 mb:anl::val=282.1
113:6640256:d=2010050806:TMP:700 mb:anl::val=284.2
120:7112632:d=2010050806:TMP:750 mb:anl::val=286
127:7585314:d=2010050806:TMP:800 mb:anl::val=289.1
134:8055101:d=2010050806:TMP:850 mb:anl::val=291.8
141:8545830:d=2010050806:TMP:900 mb:anl::val=294.6
148:9033256:d=2010050806:TMP:925 mb:anl::val=296.2
155:9515141:d=2010050806:TMP:950 mb:anl::val=297.4
162:9986444:d=2010050806:TMP:975 mb:anl::val=299.5
169:10444342:d=2010050806:TMP:1000 mb:anl::val=301.6


Bo Zhang
Dow 824,Civil and Environmental Engineering
Michigan Tech University
1400 Townsends Drive.
Houghton, MI, 49931