Simulation of Spatial Dependence in Daily Precipitation Using a Mixture of Generalized Chain-Dependent Processes at Multisites

Recently, a single-site stochastic precipitation model called “the mixture of generalized chain-dependent processes conditioned on a climate variable” was developed. The model can effectively eliminate overdispersion—that is, underestimation in variance of seasonal precipitation total. In this paper, the single-site model is further developed into a multisite stochastic precipitation model by driving a collection of individual single-site models, but with spatial dependence following a method proposed by D. S. Wilks. Specifically, a computationally effective algorithm for estimating the spatial dependence of precipitation occurrence is developed to replace the construction of the empirical curves in the Wilks method. An effective and straightforward approach for correcting the bias of the spatial correlation of precipitation intensity is also proposed. This model is tested on a small network of sites from a significant hydroelectric power generation region of South Island, New Zealand.