[CF-metadata] Overlapping time_bounds (running mean data)

From: Durack, Paul J. <durack1>
Date: Thu, 12 Mar 2015 00:24:46 +0000

Hi folks,

I?m generating a file which contains annual pentadal averaged data - so
effectively a 5-year running mean saved with an annual time step. The file
looks like:

---
dimensions:        
                   
        time = UNLIMITED ; // (56 currently)
                   
        bound = 2 ;
                   
        level = 26 ;
        latitude = 180 ;
        longitude = 360 ;
variables:
        float time(time) ;
                time:bounds = "bounds_time" ;
                time:units = "days since 1955-1-1 0:0:0.0" ;
                time:long_name = "time" ;
                time:standard_name = "time" ;
                time:calendar = "gregorian" ;
                time:axis = "T" ;
        float bounds_time(time, bound) ;
...
data:
time = 913, 1278.5, 1644, 2009, 2374, 2739.5, 3105, 3470, 3835, 4200.5,
    4566, 4931, 5296, 5661.5, 6027, 6392, 6757, 7122.5, 7488, 7853, 8218,
    8583.5, 8949, 9314, 9679, 10044.5, 10410, 10775, 11140, 11505.5, 11871,
    12236, 12601, 12966.5, 13332, 13697, 14062, 14427.5, 14793, 15158,
15523,
    15888.5, 16254, 16619, 16984, 17349.5, 17715, 18080, 18445, 18810.5,
    19176, 19541, 19906, 20271.5, 20637, 21002 ;
bounds_time =
  0, 1826,
  365, 2192,
  731, 2557,
  1096, 2922,
...
---
I?m wondering what the most CF-like way of creating these bounds?
Currently the bounds are specified as:
Index 1:2
1955-1-1 0:0:0.0 -> 1959-12-31 12:59:59.0
1956-1-1 0:0:0.0 -> 1960-12-31 12:59:59.0
And time values as above:
Index 1:2
1957-7-2 0:0:0.0
1958-7-2 12:0:0.0
When I try and load the file using Ferret, this throws a warning.. Which
makes me think I?m not doing things correctly:
Ferret v6.93
yes? use file.nc
 *** NOTE: Axis definition error on axis: time. Bounds describe cells that
overlap one another
 *** NOTE: Error in bounds "bounds_time" or bounds do not enclose point on
axis time
 *** NOTE: Substituting coordinate midpoints
Are there any tips for me regarding this, I wasn?t able to find anything
clear (at least to me) in the v1.7.2 Draft CF document.
Cheers,
P

Received on Wed Mar 11 2015 - 18:24:46 GMT