[CF-metadata] proposed additions to the standard name table

[Jonathan Gregory]

Dear Jamie

I propose that we add these on Friday 20th. At the same time, I propose we
also add sea_water_pressure (Pa), proposed by Mike McCann. Since dbar is
dimensionally equivalent to Pa, it is also OK as a unit of pressure.

> Given many of these are generated from existing standard names a natural
> question to ask is whether you should allow software to auto generate new
> names.

I think software could try to generate a name automatically but use it only
if it is in the standard name table.

We could also provide a way to propose standard names online, that could
include generating them from existing names, following the guidelines. However
they would still be subject to approval. Some possible generated names, for
example, may already exist under a different name, because there's more than
one way of doing it, or a more familiar term exists.

Best wishes

Jonathan