[CF-metadata] [CF Metadata] Question about ancillary variables/formula terms variables

From: David Hassell <d.c.hassell>
Date: Mon, 21 Dec 2015 15:41:33 +0000

Hello,

I was wondering if anyone has ever had use for an ancillary variable
(or data variable pointed to from a formula_terms attribute), having a
size 1 dimension which the "parent" field does *not* have. The
convention do not say anything about this.

For example:

  dimensions:
    t = 1;
    x = 96;
    y = 73;
  
  variables:
    float q(x, y) ;
      q:standard_name = "specific_humidity" ;
      q:units = "g/g" ;
      q:ancillary_variables = "q_error_limit" ;
  
    float q_error_limit(t, x, y)
      q_error_limit:standard_name = "specific_humidity standard_error" ;
      q_error_limit:units = "g/g" ;
  
  
Similary for a scalar coordinate variable, which is logically
equivalent to the size 1 dimension case (this time shown on a formula
terms variable):
    
  dimensions:
    x = 96;
    y = 73;
    z = 19;
      
  variables:
    float q(z, x, y) ;
      q:standard_name = "specific_humidity" ;
      q:units = "g/g" ;
  
    float z(z):
      z:standard_name = "atmosphere_hybrid_height_coordinate";
      z.formula_terms = "a: var1 b: var2 orog: var3"

    float var3(x, y):
      time:coordinates = "time";

    float time:
      time:standard_name = "time";
      time:units = "days since 2000-12-1";
    

Thanks for your help,

All the best,

David

--
David Hassell
National Centre for Atmospheric Science (NCAS)
Department of Meteorology, University of Reading,
Earley Gate, PO Box 243,
Reading RG6 6BB, U.K.
Tel   : +44 118 3785613
E-mail: d.c.hassell at reading.ac.uk

Received on Mon Dec 21 2015 - 08:41:33 GMT