A comprehensive study across methods and time scales to estimate surface fluxes from Lake Kinneret, Israel

Estimation of surface fluxes in general, and evaporation rates over lake surfaces in particular, is a difficult task. While previous studies of Lake Kinneret, Israel, have looked at evaporation rate using a single timescale or single measurement method, this is the first comprehensive study to reconcile and explain the differences between a variety of measurement and calculation methods (pan evaporation, water and heat balance, aerodynamic methods and Penman simplified methods) across a multitude of temporal scales (10 min, 1 h, daily, monthly). The cross validation of the methods suggests that the hourly calculation with the aerodynamic methods may result in a better estimation of the monthly Bowen Ratio for the energy balance methods, and therefore may increase its reliability. We also show that comprehensive measurements and calculations of monthly heat storage change in the lake can be used to verify the hourly results of the hydrodynamic method, and the daily calculations of the Penman's equation method. Moreover, using the Penman's equation it is suggested that daily Pan A evaporation measurements are nearly similar to the evaporation from the deep water lake when the heat storage change is not taken into account. It is suggested that subject to data availability, the cross validation of multiple methods increases the reliability and confidence of the measured and calculated surface fluxes.