Comparison of the New Drought Index with various well-known drought indices

Abstract

This article introduces the New Drought Index (NDI) to a wide scientific and professional society. This index, relatively simple to apply, was published by Bonacci et al. in Croatia in 2022 and international journals in 2023. Thus far, it has been tested in many countries on four continents. The main strength of NDI is that it uses only two parameters: precipitation and air temperature for a certain time period (month, season, or year). In this research, NDI was tested on a monthly basis for two Croatian regions, continental (meteorological station Donji Miholjac) and coastal region (meteorological station Split). The results were compared with those of drought severity obtained using the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Rainfall Anomaly Index (RAI), and Aridity Index (AI). The period of analysis was between 1981 and 2022. The best correlation was between both regions' NDI and SPEI (> 0,7).