sapflow bug?

[jennykowalcz]

In a recent FATES-Hydro simulation with API 36, FATES_SAPFLOW is uniformly zero, but FATES_SAPFLOW_SZPF is not. Also, FATES_SAPFLOW_SZPF values seem too low and some are negative. I'll see if I can track this down.

[samsrabin]

Seems like FATES_SAPFLOW is zero because it's never actually calculated in update_history_hydraulics().

[jennykowalcz]

Seems like FATES_SAPFLOW is zero because it's never actually calculated in update_history_hydraulics().

Yes! I looked at this with @ckoven, @JessicaNeedham, and @mpaiao and we realized that's the case. As for the values of FATES_SAPFLOW_SZPF being quite low compared to observed values, @ckoven realized it's because it is being calculated per unit ground area (as opposed to per unit sapwood area). So the plan is to add sapwood area as a history variable.