A New Approach for Drought Evaluation by Using the SPI Methodology

Abstract

Drought management and its evaluation are directly related to the appropriate methodology used for such purposes. In this context, this paper aims to present a model recently developed that provides reliable outputs of the Standard Precipitation Index (SPI). The products obtained by applying this platform are computed based on monthly precipitation data from various meteorological stations, using at least a 30-year series. Additionally, the SPI values obtained are compared with other known software used in this field and analyzing as well as the errors produced by some factors to the final SPI model outputs. Spearman’s rank correlation coefficient [ρ] between paired SPI series computed for the selected stations brings up the strength of the association between two SPI series produced by different models. It was computed also referring to different lengths of SPI data series, coming from each software, but for the same time frame of data. Also, to see and compare the product of 4 analyzed software has been calculated the Agreement Index [d], which is sensitive to differences between two variables. Furthermore, the new model provides data on the frequency of the SPI drought index and monthly precipitation, categorized and presented in graphs and various formats that are compatible and useful for other purposes.