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How are CMIP6 "evspsbl" and "hfls" variables calculated from CESM output?

The variables "evspsbl" ( Evaporation Including Sublimation and Transpiration) and "hfls" (Surface Upward Latent Heat Flux) are very similar in character and I am unsure how these fields are calculated from the atmospheric fields that are part of the standard output. Comparing CMIP6 data from CESM for these two variables reveals that throughout the tropics and parts of the mid-latitudes (especially in the SH) hfls is just evspsbl scaled by the latent heat of vaporization. The only differences between them are evident over the high latitudes. This indicates that one needs additional information about snow and ice in those latitudes to calculate one of the variables (I presume hfls). The only relevant variable in the CESM monthly outputs is LHFLX, but this doesn't seem to be enough. I am assuming that:

evspsbl = LHFLX / latent_heat_of_vapourization
hfls = LHFLX + some other stuff

Could someone please point me to specific expressions that are used in the generation of these CMIP6 variables?