Proposed guidelines for constructing standard names of chemistry and biological parameters in PRISM and CF

Change log:

Version 1.4 by Peter van Velthoven: various additions based on input by the ocean biogeochemists.

Previous versions:
Version 1.3 by Peter van Velthoven: modifications based on further discussions with Jonathan Gregory .
Version 1.2, 25 May 2003, modifications based on comments by Jonathan Gregory
Version 1.1, 28 february 2002, first draft

1. Abbreviations for chemical species

Only the standard_names co2, so4 and o3 are currently defined in the CF standard name guidelines. All others need to be proposed to the CF group. For consistency with all the others co2, so4 and o3 should be made obsolete (provide aliases for the few that use them). They should be replaced by carbon_dioxide, sulfate_aerosol and ozone.
For water vapor there is no standard_name h2o, but the standard_name specific_humidity (kg/kg) has been defined in the hydrology table. Note that this is a mass_fraction or mass mixing ratio. Species quantities should preferably be archived as volume mixing ratios (mole_fraction) with canonical unit dimensionless (parts per volume). Aerosols are an exception; mass_concentration (with canonical unit kg m-3) seems more suitable for aerosols.

All standard names should be in English spelt the American way.

The atmospheric chemical species are all in one of the following categories:

• 1.1(simple) chemical species
• 1.2 lumped species (e.g. for CBMIV-chemistry)
• 1.3 families
• 1.4 aerosols

1.1 Abbreviations for (simple) chemical species

* already defined in CF

** for ozone mass_fraction_of_o3_in_air and mole_fraction_of_o3_in_air have already been defined. The first is a mass mixing ratio, the second a volume mixing ratio. The atmospheric chemists prefer mass_fraction_of_ozone_in_air and mole_fraction_of_ozone_in_air as standard_names. See the list of constructs below.

*** used both in the atmosphere and the ocean (O3, DMS)

1.2 Abbreviations for chemical species: lumped species

In some chemical schemes, such as CBM IV, chemical species are lumped, i.e. a certain reaction rate is associated with a certain group of species showing similar chemical behaviour. In lumping, correctors may need to be added to get the correct chemical behaviour. The following standard_names will be used for lumped species:

Here R is CH3+C2H5+... and X is CH3N+C2H5N+.. If _higher_than_2_ is included in the name, CH3 resp. CH3N are not included in the sum of compounds.
Perhaps a prefix such as cb4_ should be used to identify the lumping scheme.

1.3 Abbreviations for families of species

The following standard_names refer to families of species:

1.4 Abbreviations for aerosols

The following standard_names refer to aerosol species:

2. Abbreviations for biological ocean species

3. Constructing new standard names

I propose the following guidelines for the construction of further standard_names of atmospheric chemistry parameters:

* if fluxes would be expressed in kg/(m2s), one would have to know the atomic mass of the particular species for conversion to mass. In practice not always the same number is used for this. E.g. for NOx the mass of N and of NO2 are both sometimes used. Hence molecules/(m2s) or moles/(m2s) would seem preferable.

*** advection, diffusion, convection, scavenging, evaporation, emission (the last is used for volume emissions such as from aircraft and lightning)

**** atmosphere_mole_content_of_.. has units mole m-2. Note that many other content variables have unit kg/m2 (as for so4, sulfate aerosol); see also *.

In order to describe size ranges of aerosols an extra dimension should be used.

In order to describe in-cloud processes the standard-names may need to be catenated with cloudy:

In order to describe tracers originating from a certain atmospheric compartment use the following construct:

The following are guidelines for the construction of further standard names of oceanic chemistry and biological parameters:

4. Chemical variables/properties