Dear all,
Please find an updated version (3) of the aerosol and chemical standard
names at
http://wiki.esipfed.org/index.php/CF_Standard_Names_-_Proposed_names_for_TF_HTAP
This email is in response to the comments on standard names for aerosols
and chemistry concerning coordinate variables.
I understand the purpose of using coordinate variables for quantities
dependent on other (coordinate-) variables. However, under the condition
is that the coordinated variables take many values (like spatial
coordinates). It does not make sense to use coordinate variables, if
there are only very few used (like pm? for particle size). Maybe a
minimum of probable values for the coordinate variables could be 10.
Otherwise the information should be included in the standard_name.
This gives the following CF standard_names for aerosols/chemistry:
-particle sizes (pm?) would be part of the names, not a coordinate
-standardization of the rel. humidity RH at which the particle size is
given is desirable, and as little as possible values should be used in
the community. Hence, the RH should be part of the standard_name.
-sensitivity studies/tagged tracers
There are several CO tracers used in the HTAP experiments, given here
with there variable names:
1 vmr_codirect CO_with_lifetime_of_25_days
2 vmr_cofromch4 CO_due_to_methane_oxidation
3 vmr_cofromavoc CO_due_to_oxidation_of_anthropogenic_NMVOC
4 vmr_cofrombvoc CO_due_to_oxidation_of_biogenic_NMVOC
5 vmr_cofromea CO_due_to_emissions_from_East_Asia
6 vmr_cofromeu CO_due_to_emissions_from_Europe_and_North_Africa
7 vmr_cofromna CO_due_to_emissions_from_North_America
8 vmr_cofromsa CO_due_to_emissions_from_South_Asia
I do not think that a standard_name should be defined for those, this
should go into a coordinate variable. Is it possible to have a
coordinated variable that specifies the tag?
float vmr_cofromch4(time,lev,lat,lon,tag);
VMR_CO:unit="1";
VMR_CO:coordinates="tag_name";
VMR_CO:standard_name="mole_fraction_of_CO_in_air";
double time(time) ;
time:long_name = "time" ;
time:units = "days since 1990-1-1 0:0:0" ;
float lat(lat) ;
lat:long_name = "latitude" ;
lat:units = "degrees_north" ;
float lon(lon) ;
lon:standard_name = "longitude" ;
lon:long_name = "longitude" ;
lon:units = "degrees_east"
char tag_name(tag,strlen) ;
and then in the tag_name variable the experiments would be described as
given above. Sensitivity studies with tagged tracers are widely used in
model studies and it seems to me, that is is useful to define a suitable
strategie for CF.
-wavelength for aerosol optical depth
A coordinate variable could probably be used in this case, as many
wavelengths can be used.
Best regards,
Christiane
--
Christiane Textor
Service d'A?ronomie INSU CNRS, Tour 46, RDC # 2
Universit? Pierre et Marie Curie, Boite 102
4 place Jussieu
75252 Paris C?dex 05
France
Tel: ++33 1.44.27.21.82
Fax: ++33 1.44.27.21.81
Email: christiane.textor at aero.jussieu.fr
Received on Thu Oct 05 2006 - 11:24:49 BST
