[CF-metadata] Composite area types in CMIP6 data

martin.juckes at stfc.ac.uk martin.juckes at stfc.ac.uk
Fri Jan 6 05:36:03 MST 2017


Hi David,

Yes, "type" and "ftype" are conceptually independent. "pasture" refers to a land usage category and "C4" refers to a plant functional type which can occur in and land usage category.

cheers,
Martin
________________________________
From: David Hassell [david.hassell at ncas.ac.uk]
Sent: 06 January 2017 12:24
To: Juckes, Martin (STFC,RAL,RALSP)
Cc: Jonathan Gregory; Karl Taylor; Pamment, Alison (STFC,RAL,RALSP); chris.d.jones at metoffice.gov.uk; cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Composite area types in CMIP6 data

Hello Martin,

A potential issue with specifying two scalar coordinate variables is that each one must be interpreted as spanning an independent, size 1 dimension (as clarified in #104<http://cf-trac.llnl.gov/trac/ticket/104#comment:64>). Is that the intention, here? To combine them onto one dimension you would have to make the scalar coordinates into 1-d coordinates:

dimensions:
    x = 1 ;
variables:
    float pastureFracC4(x, time, lat, lon) ;
        pastureFracC4:coordinates = "type ftpye" ;
        pastureFracC4: standard_name = "area_fraction";
    char type(x, strlen) ;
        type:long_name = "Pasture Land" ;
        type:standard_name = "area_type" ;
    char ftype(x, strlen) ;
        ftype:long_name = "Plant Functional Type" ;
        ftype:standard_name = "area_type" ;
data:
type = "patsures" ;
ftype = "c4_plant_functional_types";

I suppose it's a question of the science that your trying to capture...

All the best,

David

On 6 January 2017 at 11:43, <martin.juckes at stfc.ac.uk<mailto:martin.juckes at stfc.ac.uk>> wrote:
Hello,

In CMIP6 we have a request for some data on pasture land with C4 functional type. We already have CF area types for pasture and c4 plants in general. We could construct the required information as follows:

    float pastureFracC4(time, lat, lon) ;
        pastureFracC4:coordinates = "type ftpye" ;
        pastureFracC4: standard_name = "area_fraction";
        ......
    char type(strlen) ;
        type:long_name = "Pasture Land" ;
        type:standard_name = "area_type" ;
    char ftype(strlen) ;
        ftype:long_name = "Plant Functional Type" ;
        ftype:standard_name = "area_type" ;
data:
 type = "patsures" ;
 ftype = "c4_plant_functional_types";

This would provide the information that the variable pastureFracC4 refers to areas that are both "pastures" and "c4_plant_functional_types". An altenative would be to add a new area type, but I have the feeling that the area_type list will become unmanagable if we keep adding new terms for combinations of existing terms.  Can anyone see a problem with using two area_type coordinates?

regards,
Martin
_______________________________________________
CF-metadata mailing list
CF-metadata at cgd.ucar.edu<mailto:CF-metadata at cgd.ucar.edu>
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata



--
David Hassell
National Centre for Atmospheric Science
Department of Meteorology, University of Reading,
Earley Gate, PO Box 243, Reading RG6 6BB
Tel: +44 118 378 5613
http://www.met.reading.ac.uk/



More information about the CF-metadata mailing list