A Matlab based ordinary Kriging model developed for rainfall spatial interpolation over macro regions and a case application

An automated ordinary Kriging model based on Matlab platform(MatOK) was specially developed for rainfall spatial interpolation over macro regions. The proposed model has three main traits compared with other ordinary Kriging(OK) models. Firstly, in the part of rainfall spatial variogram computation, the parameters of theoretical variogram are optimized using the Shuffled Complex Evolution method-University of Arizona(SCE-UA). Secondly, in the part of OK equation estimation, daily and other short time step rainfall interpolation is improved by adding a process of precipitation occurrence probability(POP) calculation. Thirdly, the model's numerical stability is raised through OK equation's standardization. Then, based on 325 rain gauges observations during 2003-2009 in the Ganjiang River Basin with a drainage area of 83374km2, a case application of yearly, monthly and daily rainfall spatial interpolation using MatOK was conducted. Results preliminarily show that MatOK is feasible for rainfall spatial interpolation over macro regions.