Climatic models of atmospheric moisture are derived by analysing ten years of three-hourly surface readings of mixing ratio at 31 locations in the Australian region. These models consist of annual and semi-annual cycles, a diurnal cycle, and interaction terms between the annual and diurnal cycles. Both average and standard deviation effects are modelled as harmonic functions of time. For application to a larger study based on daily radiosonde and satellite soundings, it was necessary to obtain a method of predicting the diurnal and interaction parameters for coastal and island sites from the annual parameters in the climatic model. The resulting equations also incorporate latitude. The residual variations in atmospheric moisture are small enough for the climatic models to have useful predictive capability.
Dunsmuir et al. (1990) studied this question.