The Effect of Relative Humidity on Eddy Covariance Latent Heat Flux Measurements and its Implication for Partitioning into Transpiration and Evaporation

•The underestimation of hourly LE at high RH is pronounced at closed-path sites.•Well-established methods (BWRC and AEIL) do not correct for the LE underestimation.•The machine learning based empirical method is helpful to address the RH-related error.•The RH-dependent LE error affects T/ET and WUE at high RH conditions.