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ESCOMP / atmospheric_physics

CCPP-enabled Atmospheric Physics
Apache License 2.0
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Variables "z" and "zm" are geopotential height (at mid-levels), not geopotential #11

Closed nusbaume closed 4 years ago

nusbaume commented 4 years ago

In the Kessler.meta and geopotential_t.meta files, the variables z and zm should be the geopotential height at mid-levels. However, their standard names have them labeled "geopotential", which is a different physical quantity.

These standard names should thus be modified to state "geopotential height", not just "geopotential". Otherwise there is a high risk that a future user or developer will use these variables in an incorrect way.

gold2718 commented 4 years ago

The standard name library has been moved and the new repo is here. For now, the standard name page is just a file in that repo. The new names are geopotential_height and geopotential_height_at_interface.

gold2718 commented 4 years ago

One issue is whether the name geopotential itself is ever really correct in current usage. While I took this name from GFS physics (e.g., the standard name library currently has geopotential_at_surface), it is really geopotential_per_unit_mass. Is it worth trying to get that change accepted?

nusbaume commented 4 years ago

In an ideal world, yes, I think it would be good to have the names be as exact as possible.

However, if that is difficult to change then I personally believe it is ok to not include the "per_unit_mass" text. The reason being that if most of our users have an atmospheric science background, then the fluid dynamics equations they were exposed to were likely derived in a "per unit mass" framework, so the user would likely implicitly assume that the variables are all per unit mass, at least in most situations.

gold2718 commented 4 years ago

This was fixed in #8.