[gradsusr] Problem when plotting daily means from NetCDF
Daniel Klaus
Daniel.Klaus at awi.de
Thu Sep 16 06:51:16 EDT 2010
Dear all,
I have a strange problem with GrADS:
I use a NetCDF file including daily averaged variables (fields). The
file contains all required dimensions x, y, z, time=UNLIMITTED;//(397
currently), where the time coordinate varies from 1 to 397, which
corresponds to a time range of 13 months starting at the 1st of August
2007. I open the file with "xdfopen" using a descriptor file similar to:
========================================================
DSET ^file_avg.nc
TITLE 'Model daily means of prognostic variables'
UNDEF -2.56E33
XDEF lon
YDEF lat
ZDEF lev
TDEF time 397 LINEAR 0Z01Aug2007 1DY
=========================================================
Lon, lat and lev (x,y,z) as well as the variables (Temperature T,
specific humidity Q, ...) are well defined directly in "file_avg.nc" and
the file can be read without any problem. In principle, all seems to be
ok, because creating graphics with respect to a certain time step (day
mean vertical profile) works normally. For instance a temperature
profile with following settings:
-------------------------------------
X is fixed Lon = 1 X = 1
Y is fixed Lat = 1 Y = 1
Z is varying Lev = 1012.05 to 0.1 Z = 1 to 60
T is fixed Time = 00Z11SEP2007 T = 42
ga-> d T
-------------------------------------
is drawed correctly but displaying a time-height cross section (contour
plot) of temperature (i.e. using a time interval) e.g. with settings
according to:
-------------------------------------
X is fixed Lon = 1 X = 1
Y is fixed Lat = 1 Y = 1
Z is varying Lev = 1012.05 to 0.1 Z = 1 to 60
T is varying Time = 00Z01AUG2007 to 00Z16FEB2008 T = 1 to 200
ga-> d T
-------------------------------------
fails. Although the time axis is drawed correctly, something stranged is
displayed in the graphic window that is really nonsense. Besides I get
the message:
------------------------------
Contouring: -0 to 2e+07 interval 2e+06
------------------------------
Now, I assume that it is a GrADS problem, because "ncview" plots the
whole 397 day period and single days as well. GrADS has obviously a
problem with the time coordinate, although I redefined it within the
descriptor file.
Has anybody an idea, what have I done wrong and what to do?
best wishes,
Daniel
_______________________________________________________
Daniel Klaus
Dipl.-Physiker (graduate physicist), PhD Student
Alfred Wegener Institute for Polar and Marine Research
Research Unit Potsdam
-Atmospheric Circulations-
Telegrafenberg A43-105
14473 Potsdam
Germany
phone: +49(331)288-2202
email: Daniel.Klaus at awi.de
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