Multiple Estimates of Lake Erie Evaporation

Evaporation from large lakes cannot be measured directly, but several methods have been developed to compute lake evaporation. Because of the Great Lakes data limitations, evaporation determined by a single method is’ not sufficiently reliable and requires verification of accuracy by different methods. Monthly evaporation from Lake Erie was derived by the water budget, selected mass transfer, and the energy budget approaches. The period of record varies with the availability of data, 1937-68 for the water budget and mass transfer methods, and 1952-1968 for the energy budget method. Evaporation determined by the water budget method was used to provide control for the other methods. The evaporation rates varied from -9 to 25 cm/month with periods of low, median, and high annual evaporation averaging approximately 80, 90 and 100 cm. The analysis of results indicates that reasonably accurate evaporation estimates during the year can be obtained by the water budget and the modified Lake Hefner mass-transfer equations.