[CF-metadata] aerosol water

[Jonathan Gregory]

Dear Christiane

> >>aerosol_water_ambient_aerosol
> >>Jonathan porposed that the name should be the other way round. I do not 
> >>agree because a 'water aerosol' would be a hydrometeor, i.e., clouds or 
> >>precipitation.
> >
> >I think I haven't understood what this name really means, sorry to say. I
> >was guessing it meant the water present in ambient aerosol. But perhaps
> >that is wrong?
> 
> Yes, this is indeed what is. I agree that the name is a bit strange as 
> it is. It was constructed consistently to the other aerosol components:
> species_<ambient/dry>_aerosol, and aerosol_water is an aerosol component 
> as for example dust or sea salt. A better name would probably be:
> 
> water_in_ambient_aerosol_in_air

I'd call it  mass_fraction_of_ambient_aerosol_water_in_air  because I would
understand ambient_aerosol_water to mean the water present in ambient aerosol.
That's the same as what you said except that two "in"s make the name harder to
interpret, I find.

best wishes

Jonathan