The paper presents a multidimensional model of nonstationary space‐time rainfall over a catchment due to a single storm event. The model is based on a conceptual representation of the essential features of an extratropical cyclonic storm. The storm is assumed to consist of a hierarchy of scales of which the smallest are the rain cells which are embedded within the small mesoscale areas, which are then embedded within the large mesoscale area or rainband. The mean and nonstationary space‐time covariance are derived for the conceptual rainfall model. In addition, the statistics and stochastic dependence structures of rainfall intensity aggregated or averaged over finite times and finite areas are also derived. The finite areas represent catchments and subcatchments over which the rainband passes. Finite times could represent the scales at which rainfall measurements are made. A rainfall generator is developed based on a quasi‐stationary approximation to the nonstationary space‐time autocorrelation derived above. The generated rainfall traces not only reproduce the specified space‐time correlations but also exhibit storm movement, the cellular structure of storms, and the birth and decay of cells arid cell clusters.
All Science Journal Classification (ASJC) codes
- Water Science and Technology