Try fixing 1M scheme for ClimaAtmos

[trontrytel]

ClimaAtmos 1-moment simulations don't work with the new release of CloudMicrophysics (v0.21). I tracked it down to us changing the "do nothing" condition in 1-moment microphysics scheme from FT(0) to eps(FT).

This PR reverts the changes. I will make a new release for CloudMicrophysics after it is merged (and ideally also #417 and #415 )

[trontrytel]

cc @szy21 - This should fix Atmos simulations

[szy21]

Thanks! It's interesting that this makes a difference to stability. Maybe eps(Float32) is too large as a threshold for things like q_rai?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.94%. Comparing base (f73555a) to head (69c170a).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #418      +/-   ##
==========================================
- Coverage   97.01%   96.94%   -0.07%     
==========================================
  Files          37       37              
  Lines        1440     1440              
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- Hits         1397     1396       -1     
- Misses         43       44       +1     

Components	Coverage Δ
src	98.88% <100.00%> (-0.08%)	⬇️
ext	69.79% <ø> (ø)

[crocicc]

Looks good to me Anna! Considering that eps(Float32) is quite large, it will even make the computation of radar reflectivity more accurate; so thank you so much for this!

[trontrytel]

Agreed. I think for Float32 its not a good condition for our water tracers. One way around it would be to consider not using base SI units for some of the microphysics variables. But for now I'll make sure that the schemes we use in Atmos use FT(0)