Theory 79/Measurement & modelling/Evaporation measurement
Pan Evaporation Is Advection Against Radiation
The claim
Pan evaporation trends can move opposite to actual evaporation when the ratio of advection to radiation changes, which is why declining pans coexisted with increasing evaporative demand.
01Mechanism
A pan is advectively coupled and radiation-driven in different proportions than a canopy.
02Prediction
Divergence should track the ratio.
03Refutation
Pan tracking actual evaporation would remove the coupling difference.