The variability of Australian tank evaporation

Tests using the larger samples of monthly evaporation (E) data (over 25 years) indicate that the distributions are not significantly different from normal. Estimates of standard deviation (σ̂E) and mean (E), of monthly evaporation have been computed for a large number of Australian stations and monthly maps showing the geographical distribution of σ̂E have been constructed. Values are a minimum over the south-east of the continent and a maximum over central and northern interior. Variability is directly proportional to mean evaporation (Ē) but at individual stations σ̂E has a climatic dependance. For example, both Alice Springs and Merredin have December values of Ē of about 12 in. but the respective sample standard deviations are 2.0 and 1.1 in.