I am exploring FLUXNET sites for actual evapotranspiration (ETP) data (I convert the energy balance closure-corrected latent heat to ETP).
I am interested in the half-hourly data. During the night we see negative values. I would like to know the reason or physical process behind this.
Can physically-based hydrological models handle this situation? (: estimating negative half-hourly ETPs)
There are some discussion in web about how to handle the negative values of potential ETP, but not easy to find a solid discussion about the actual ETP in this case.