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[IDV #ZNZ-304595]: time format

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  • Subject: [IDV #ZNZ-304595]: time format
  • Date: Thu, 03 Jul 2008 07:51:00 -0600
Hi-

> > > Full Name: Aude Valade
> > > Email Address: address@hidden
> > > Organization: UC Davis, department of Atmospheric Sciences
> > > Package Version: 2.5 build date:2008-05-08 07:05 UTC
> > > Operating System: Windows XP
> > > Hardware: Java: home: C:\Program Files\Java\jre1.6.0_02 version: 1.6.0_02
> > j3d:1.3.2 fcs (build12)
> > > Description of problem: Hi,
> > > I have a .nc file, supposedly representing diabatic heating data. The
> > dimensions are lat, lon, time where time is in the format YYYYMMDDHH
> > (example 1979010100 is the first, 2007111218 is the last one. )
> >
> > Is this stored as a character string, or an integer?  If the latter, how
> > are the
> > units defined?
> >
> It is stored as a double, the ncl_filedump of the file returns:

This is problematic.  There is no physical unit that can be specified to turn
YYYYMMDDHH into a time since it is an artificial representation of a time.
It needs to be something like "hours since 1979-01-01 00:00:00" to be able to 
convert to a time with the appropriate values.

> filename:       diabatic_heating
> path:   diabatic_heating.nc
> file global attributes:
> creation_date : Mon Jun  9 11:04:02 PDT 2008
> Conventions : None
> source_file : original-file.nc
> title : NCL Efficient Approach to netCDF Creation
> long_name : Diabatic Heating
> dimensions:
> time = 42165  // unlimited
> lat = 73
> lon = 144
> variables:
> double time ( time )
> _FillValue :   -999
> 
> float lat ( lat )
> La1 :  90
> Lo1 :   0
> La2 :  -90
> Lo2 :  -2.5
> Di :   2.5
> Dj :   2.5
> units :        degrees_north
> GridType :     Cylindrical Equidistant Projection Grid
> long_name :    latitude
> 
> float lon ( lon )
> La1 :  90
> Lo1 :   0
> La2 :  -90
> Lo2 :  -2.5
> Di :   2.5
> Dj :   2.5
> units :        degrees_east
> GridType :     Cylindrical Equidistant Projection Grid
> long_name :    longitude
> 
> float diabatic_heating ( time, lat, lon )
> center :       Japanese Meteorological Agency - Tokyo (RSMC)
> long_name :    Diabatic Heating
> units :        W/m2
> _FillValue :   -999
> level_indicator :      1
> gds_grid_type :        0
> parameter_table_version :      3
> parameter_number :     218
> forecast_time :        6
> initial_time : 01/01/1979 (00:00)
> 
> 
> 
> >
> >
> > > However, when I display the data in IDV, the time is given in a strange
> > format: 0063-09-18 05:01:46Z for example.

Unfortunately, we are parting this wrongly, thus the bad time.

> > > In order to understand better what is going on I tried to display time
> > series/probe but I got this error message.
> >
> > Can you provide a sample file?  If it's big, can you put it on a web or FTP
> > site where I can download it instead of sending it as an attachment?
> >
> I do not have a FTP, do you have one?

We don't.  How big is the file?

Don Murray

Ticket Details
===================
Ticket ID: ZNZ-304595
Department: Support IDV
Priority: Normal
Status: Open