[CF-metadata] Use of 'omega' in standard name list

From: Jonathan Gregory <j.m.gregory>
Date: Sun, 14 Dec 2003 23:08:39 +0000

Dear Bryan

> For years I taught GFD where I defined omega as "vertical velocity in pressure
> coordinates"

Thanks for this suggestion.

> I don't believe there is any ambiguity in sign ... velocity in pressure
> coordinates can only mean dp/dt ...

I'm not sure about that. It's obvious to you, but someone who hadn't used it
before might be worried about positive meaning downwards, unless it is stated
somehow in the name.

Also, "velocity" means m s-1 everywhere else the word is used. "in pressure
coordinates" might be interpreted as indicating just that it is a function of
pressure as the vertical coordinate rather than height, like saying "temperature
on pressure levels". Of course, the vertical velocity in m s-1 is actually
called upward_air_velocity regardless of the vertical coordinate, but I guess
the possibility of misinterpretation exists. That's why I chose "expressed_as".

> I find "expressed...tendency of pressure" to be clumsy ... and I wouldn't want
> it on any plots where I used the standard name ...

Many of the standard names are clumsy, because they aim to be explicit. The
long_name can be used to give a title you'd prefer to appear on a plot.

However, I agree that your phrase is neater and more familiar. Maybe my
concerns are unfounded. I wonder what other people think.

Cheers

Jonathan
Received on Sun Dec 14 2003 - 16:08:39 GMT