[gradsusr] Problem when plotting daily means from NetCDF

[Daniel Klaus]

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