New Representation of Plant Hydraulics Improves the Estimates of Transpiration in Land Surface Model

Transpiration represents more than 30% of the global land–atmosphere water exchange but is highly uncertain. Plant hydraulics was ignored in traditional land surface modeling, recently plant has been found to play an essential role transpiration simulation. A new physical-based representation hydraulic schemes (PHS) developed and implemented Common Land Model (CoLM). However, it unclear what extent PHS can reduce these uncertainties. Here, we evaluated against measurements obtained at 81 FLUXNET sites. The each site estimated using empirical evapotranspiration partitioning approach. metric scores defined by International Benchmarking Project (ILAMB) were used evaluate model performance compare with that CoLM default scheme (soil moisture stress (SMS)). bias score higher SMS for most sites, significant improvements semi-arid arid sites where limited soil moisture. redistribution optimized supply thus improved estimates. In humid no improvement seasonal or interannual variability simulated PHS, which be explained insensitivity demand coupled photosynthesis response precipitation. better captured SMS, interpreted drought sensitivity transpiration. Arid widespread expected expand due climate change, there urgent need couple models.