The Powersdi: An R-Package for Implementing and Calculating the SPI and Spei Using Data from the Nasa-Power Project
44 Pages Posted: 9 May 2023 Last revised: 27 Nov 2023
Abstract
The Standardized Precipitation (SPI) and Standardized Evapotranspiration-Precipitation (SPEI) indices are important tools for monitoring drought events, but the low density of weather station networks limits their use in many regions. To address this issue, we developed the PowerSDI R-package, which calculates these two indices using gridded-data from the NASA-POWER project (NASA-SPI and NASA-SPEI). The package includes three functions (ScientSDI.R, Reference.R, and Accuracy.R) that evaluate how well the NASA-SPI and NASA-SPEI meet conceptual assumptions required for their calculation and use. The OperatSDI.R function allows users to download NASA-POWER data for specific monitoring periods, greatly reducing the running time of the function. The package adopts a quasi-weekly basic time scale, allowing for four index calculations per month. The PowerSDI package provides a solid scientific basis for using NASA-POWER data in drought monitoring systems, which can help improve drought preparedness and response efforts worldwide.
Keywords: standardized drought indices, drought monitoring, R-software
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