“…The flux in REA is found as the product of the difference between accumulated scalar concentrations (∆C), wind standard deviation (σ w ), and an empirical coefficient β. The interpretation and determination of the empirical coefficient β have remained the primary questions concerning the REA method [Baker, 2000, Katul et al, 2018, Vogl et al, 2021. While the theoretical value of β derived assuming a Gaussian distribution for wind and scalar is β ≈ 0.63 [Wyngaard and Moeng, 1992], observed average values of β typically range between 0.47 and 0.63 and exhibit substantial run-to-run variability [Gao, 1995, Katul et al, 1996, Tsai et al, 2012, Grelle and Keck, 2021.…”