EAMxx: Add diagnostic output that keeps track of vertical motions (and other thermodynamic variables) in updrafts and downdrafts

[crterai]

It would be great if we had a way of diagnosing mass flux (keep track of only positive values of omega or vertical velocity, the same for downward, and then the fraction of time it is positive or negative)- so we can better diagnose vertical mixing from resolved circulations without having to save instantaneous snapshots of vertical motion to calculate this.
https://glossary.ametsoc.org/wiki/Convective_mass_flux

Similarly, if we can keep track of vertical transport of moisture, potential temperature, and other variables under updraft or downdraft conditions, we can also diagnose vertical mixing of moisture, heat, etc.

[mahf708]

From @hassanbeydoun: "@mahf708, mass flux shoudn't be too complicated. We need a flag on a vertical velocity threshold (say w > 1 m/s), we then need to conditionally average those vertical velocities. We also need to tally the number of times the flag is raised"

[crterai]

Ideally, we'd have a mass flux diagnostic for both thresholds of 1 m/s and 0 m/s. I understand in the literature, a minimum threshold w is used for reporting convective mass flux, but if we also track a mass flux with a threshold of 0 m/s, then we'll be better able to track all vertical transport online.
And @hassanbeydoun, I assume thresholding at 1 m/s captures the convective updraft mass flux. Would you want to keep track of convective downdraft mass flux as well?

[mahf708]

xref: #7491
xref: #7508