[CF-metadata] new named fields for ocean

From: Jonathan Gregory <j.m.gregory>
Date: Mon, 12 Jan 2009 18:31:34 +0000

Dear Steve

I would prefer keeping the sea_water in sea_water_pressure:
> sea_water_pressure_at_the_sea_water_surface
> sea_water_pressure_at_sea_floor
It might seem redundant in this context but it corresponds to the standard
name of sea_water_pressure, analogous to air_pressure. That means the
pressure that exists in the medium of sea water. It doesn't imply that it is
caused only by overlying sea water.

> I too find this name unappealing. I suggest the following alternatives:
>
> temperature_flux_due_to_rainfall_expressed_as_heat_flux_into_sea_water
> --> heat_flux_into_sea_water_due_to_rainfall_mass_flux
>
> temperature_flux_due_to_evaporation_expressed_as_heat_flux_out_of_sea_water
> --> heat_flux_out_of_sea_water_due_to_evaporative_mass_flux
>
> temperature_flux_due_to_runoff_expressed_as_heat_flux_into_sea_water -->
> heat_flux_into_sea_water_due_to_runoff_mass_flux
>
> These new names are A/ shorter, B/ more directly what is intended
> physically; i.e., a heat flux due to a mass flux.

When we had the earlier discussion, I proposed temperature flux because I
think that temperature multiplied by mass flux is a quantity that people
have to be careful with because of its arbitrary zero. In that respect it
is not like a genuine heat flux. You can't tell what heat is being added
unless you know the temperature and the mass of the water it's being added
to. I thought "temperature flux" would draw attention to the way it was
evaluated. To be more explicit, it is
  product_of_rainfall_temperature_and_rainfall_flux_expressed_as_heat_flux
Without expressed_as_heat_flux it would be in K kg m-2 s-1 rather than W m-2.
Maybe it's OK to omit _into_sea_water since rainfall flux is generally assumed
to be at the surface, and this quantity exists equally over land. We would use
cell_methods to restrict it to the sea part of the gridbox. The definition
should also state what the zero of temperature is.

Why do we want these quantities? Would be clearer and easier to ask for the
rainfall_temperature and the
temperature_of_water_flux_into_sea_water_from_rivers? I'm sorry that I hadn't
thought about the evaporation before. I'm not sure what this means: isn't the
evaporating water necessarily at surface temperature? The heat carried away
is just the latent heat.

Best wishes

Jonathan
Received on Mon Jan 12 2009 - 11:31:34 GMT