Potential bug(?) in GrADS when sub-hour data-file names are generated from template
Henryk Modzelewski
henryk at EOS.UBC.CA
Mon Jun 26 19:49:45 EDT 2006
Hi,
Let me explain shortly. Quite recently we increased the frequency of
our NWP output to 30 minutes (from 1 hour). We have been using GrADS
for years and they worked perfectly fine with hourly output based on
template option, but have problems with sub-hourly. Basically, I
suspect that GrADS gets the data from the wrong file whenever time
index ('set t' with template) does not point to an equal hour.
To investigate, I have got the source code for 1.9 (although we use
1.8 daily) from the web page and compiled gradsc on Linux system. I
added extra print statement just before 'return (fnout);' in gafndt
(gautil.c). The .ctl file and the result of print statement are
below. You will notice that whenever the filename is for the data-
file off an equal hour, then an extra hour is added to the forecast
time; the first off-hour file is skipped (g4.0606210000_0130.dat
instead of g4.0606210000_0030.dat), and the one-before-last is beyond
the length of the forecast (g4.0606210000_6030.dat instead of File
from template g4.0606210000_5930.dat).
I did not have a chance to get to the source of the problem, but I
identified the same behavior for Irix and Mac OS, so it does not seem
to be platform specific.
Am I doing something wrong in the template? I would appreciate any
help and/or suggestions.
Here is my .ctl:
++++++++++++++++++
DSET ^g4.%iy2%im2%id2%ih2%in2_%f2%n2.dat
OPTIONS template
TITLE MM5 data
OPTIONS big_endian
UNDEF -9999.
PDEF 210 153 nps 453.5852661 1113.1054688
-105.0000000 4.0000000
XDEF 210 LINEAR -130.2394409 0.0616600
YDEF 127 LINEAR 46.0058861 0.0566101
ZDEF 16 LEVELS
1001.00
1000.00
975.00
950.00
925.00
900.00
850.00
800.00
750.00
700.00
600.00
500.00
400.00
300.00
250.00
200.00
TDEF 121 LINEAR 00:00Z21JUN2006 30MN
VARS 38
PCPCONV 0 99 1hr accum conv pcn (
PCPTOT 0 99 1hr accum non-c pcn
PCPCONVAC 0 99 accum conv pcn (mm)
PCPTOTAC 0 99 accum non-c pcn (mm)
D2TOPO 0 99 ter elevation (m)
LAT 0 99 cross lat (degree)
LON 0 99 cross lon (degree)
ZPBL 0 99 pbl height (m)
SFCTC 0 99 2 m temperature (C)
SFCQ 0 99 2 m mixing ratio (kg
SFCU 0 99 10 m u wind (kts)
SFCV 0 99 10 m v wind (kts)
CAPE 0 99 CAPE (J/Kg)
SP 0 99 sfc pressure (mb)
SFCRH 0 99 surface rh (%)
PCPSOLID 0 99 1hr solid preci(mm)
PCPLIQ 0 99 1hr liquid preci (m
PCPSOLIDAC 0 99 Accum. solid preci(m
PCPLIQAC 0 99 Accum. liquid preci
MSLP 0 99 sea level prs (mb)
cref 0 99 composite refl (dbz)
clfrlo 0 99 low cloud fraction
clfrmi 0 99 mid cloud fraction
clfrhi 0 99 high cloud fraction
U 16 99 u wind (kts)
V 16 99 v wind (kts)
WP 16 99 vertical vel (Pa/s)
W 16 99 vertical vel (m/s)
TC 16 99 temperature (C)
Z 16 99 geopot height (dam)
TDC 16 99 dewpoint temp (C)
RH 16 99 rel humidity (%)
TH 16 99 potential temp (K)
vor 16 99 vorticity (s-1)
DBZ 16 99 reflectivity (dbz)
div 16 99 divergence (s-1)
dir 16 99 dir (degrees)
CLOUD 16 99 cloud dimensionless
ENDVARS
++++++++++++++++++
Here is what extra print statement in gafndt shows:
==================
File from template g4.0606210000_0000.dat
File from template g4.0606210000_0130.dat
File from template g4.0606210000_0100.dat
File from template g4.0606210000_0230.dat
File from template g4.0606210000_0200.dat
File from template g4.0606210000_0330.dat
File from template g4.0606210000_0300.dat
File from template g4.0606210000_0430.dat
File from template g4.0606210000_0400.dat
File from template g4.0606210000_0530.dat
File from template g4.0606210000_0500.dat
File from template g4.0606210000_0630.dat
File from template g4.0606210000_0600.dat
File from template g4.0606210000_0730.dat
File from template g4.0606210000_0700.dat
File from template g4.0606210000_0830.dat
File from template g4.0606210000_0800.dat
File from template g4.0606210000_0930.dat
File from template g4.0606210000_0900.dat
File from template g4.0606210000_1030.dat
File from template g4.0606210000_1000.dat
File from template g4.0606210000_1130.dat
File from template g4.0606210000_1100.dat
File from template g4.0606210000_1230.dat
File from template g4.0606210000_1200.dat
File from template g4.0606210000_1330.dat
File from template g4.0606210000_1300.dat
File from template g4.0606210000_1430.dat
File from template g4.0606210000_1400.dat
File from template g4.0606210000_1530.dat
File from template g4.0606210000_1500.dat
File from template g4.0606210000_1630.dat
File from template g4.0606210000_1600.dat
File from template g4.0606210000_1730.dat
File from template g4.0606210000_1700.dat
File from template g4.0606210000_1830.dat
File from template g4.0606210000_1800.dat
File from template g4.0606210000_1930.dat
File from template g4.0606210000_1900.dat
File from template g4.0606210000_2030.dat
File from template g4.0606210000_2000.dat
File from template g4.0606210000_2130.dat
File from template g4.0606210000_2100.dat
File from template g4.0606210000_2230.dat
File from template g4.0606210000_2200.dat
File from template g4.0606210000_2330.dat
File from template g4.0606210000_2300.dat
File from template g4.0606210000_2430.dat
File from template g4.0606210000_2400.dat
File from template g4.0606210000_2530.dat
File from template g4.0606210000_2500.dat
File from template g4.0606210000_2630.dat
File from template g4.0606210000_2600.dat
File from template g4.0606210000_2730.dat
File from template g4.0606210000_2700.dat
File from template g4.0606210000_2830.dat
File from template g4.0606210000_2800.dat
File from template g4.0606210000_2930.dat
File from template g4.0606210000_2900.dat
File from template g4.0606210000_3030.dat
File from template g4.0606210000_3000.dat
File from template g4.0606210000_3130.dat
File from template g4.0606210000_3100.dat
File from template g4.0606210000_3230.dat
File from template g4.0606210000_3200.dat
File from template g4.0606210000_3330.dat
File from template g4.0606210000_3300.dat
File from template g4.0606210000_3430.dat
File from template g4.0606210000_3400.dat
File from template g4.0606210000_3530.dat
File from template g4.0606210000_3500.dat
File from template g4.0606210000_3630.dat
File from template g4.0606210000_3600.dat
File from template g4.0606210000_3730.dat
File from template g4.0606210000_3700.dat
File from template g4.0606210000_3830.dat
File from template g4.0606210000_3800.dat
File from template g4.0606210000_3930.dat
File from template g4.0606210000_3900.dat
File from template g4.0606210000_4030.dat
File from template g4.0606210000_4000.dat
File from template g4.0606210000_4130.dat
File from template g4.0606210000_4100.dat
File from template g4.0606210000_4230.dat
File from template g4.0606210000_4200.dat
File from template g4.0606210000_4330.dat
File from template g4.0606210000_4300.dat
File from template g4.0606210000_4430.dat
File from template g4.0606210000_4400.dat
File from template g4.0606210000_4530.dat
File from template g4.0606210000_4500.dat
File from template g4.0606210000_4630.dat
File from template g4.0606210000_4600.dat
File from template g4.0606210000_4730.dat
File from template g4.0606210000_4700.dat
File from template g4.0606210000_4830.dat
File from template g4.0606210000_4800.dat
File from template g4.0606210000_4930.dat
File from template g4.0606210000_4900.dat
File from template g4.0606210000_5030.dat
File from template g4.0606210000_5000.dat
File from template g4.0606210000_5130.dat
File from template g4.0606210000_5100.dat
File from template g4.0606210000_5230.dat
File from template g4.0606210000_5200.dat
File from template g4.0606210000_5330.dat
File from template g4.0606210000_5300.dat
File from template g4.0606210000_5430.dat
File from template g4.0606210000_5400.dat
File from template g4.0606210000_5530.dat
File from template g4.0606210000_5500.dat
File from template g4.0606210000_5630.dat
File from template g4.0606210000_5600.dat
File from template g4.0606210000_5730.dat
File from template g4.0606210000_5700.dat
File from template g4.0606210000_5830.dat
File from template g4.0606210000_5800.dat
File from template g4.0606210000_5930.dat
File from template g4.0606210000_5900.dat
File from template g4.0606210000_6030.dat
File from template g4.0606210000_6000.dat
==================
Thanks,
Henryk
_______________________________________________________
Henryk Modzelewski
UBC EOS, Atmospheric Science Programme
#224-6339 Stores Road, Vancouver, BC V6T 1Z4, Canada
E-mail : hmodzelewski at eos.ubc.ca
Office : 604 822 4760
Mobile : 604 341 0531
Fax : 604 822 6088
"For what are we left with if there remains no mystery?
What hope might we find if we know all of the answers?"
Drizzt Do'Urden
_______________________________________________________
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