Pull in units updates from FV3

[DWesl]

Commit Queue Requirements:

• Fill out all sections of this template.
• All sub component pull requests have been reviewed by their code managers.
• Run the full Intel+GNU RT suite (compared to current baselines) on either Hera/Derecho/Hercules
• Commit 'test_changes.list' from previous step

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Description:

This PR updates units definitions to be machine-readable:

• W rather than w as a symbol for watts
• m rather than M as a symbol for meters
• Pa rather than pa as a symbol for pascals (and hPa for hectopascals)
• mbar rather than mb as a symbol for millibar

Commit Message:

* UFSWM - Update units attributes in netCDF output to be machine-readable
  * FV3 - Update units attributes in netCDF output to be machine-readable
    * atmos_cubed_sphere - Update units attributes in netCDF output to be machine-readable

Priority:

• Normal

Git Tracking

UFSWM:

• None

Sub component Pull Requests:

• FV3: STY: Use capital W and lowercase m for watts per square meter NOAA-EMC/fv3atm#859
  • atmos_cubed_sphere: STY: Use mbar and Pa for units of pressure NOAA-GFDL/GFDL_atmos_cubed_sphere#356

UFSWM Blocking Dependencies:

• None

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Changes

Regression Test Changes (Please commit test_changes.list):

• PR Adds New Tests/Baselines.

Input data Changes:

• None.

Library Changes/Upgrades:

• No Updates

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Testing Log:

• RDHPCS
  • Hera
  • Orion
  • Hercules
  • Jet
  • Gaea
  • Derecho
• WCOSS2
  • Dogwood/Cactus
  • Acorn
• CI
• opnReqTest (complete task if unnecessary)

[DusanJovic-NOAA]

I ran a subset of tests on Hera and everything looks good. @jkbk2004 This PR is ready for review and merge. It does need new baselines.