[CF-metadata] hydrosphere (or, water)

[Jonathan Gregory]

Dear Nan

> It might be worthwhile to consider replacing the term "sea_water" with 
> "water" in the standard name list, with sea_water aliased for backwards
> compatibility.

The reason for not doing that is that "water" is too vague. Not all water
is seas, rivers or lakes; some is cloud water, some groundwater, instance.
What we need is a word for a body of water whose bottom is on the solid
Earth. Maybe we should just make a up a word! I believe that the word "gas"
was invented from nothing, and that has caught on.

Cheers

Jonathan