[In Press] Spatiotemporal meteorological drought assessment : a case study in south-east Australia

An understanding on different aspects of droughts is crucial for effective water resources management. Australia has experienced notable droughts in recent years. The present study utilises Effective Drought Index (EDI) and Standardized Precipitation Index (SPI) based on six time horizons (3, 6, 9, 12, 24, and 36 months) to evaluate drought parameters such as magnitude, duration, and intensity with their onset and end in south-east Australia using data from 45 rainfall stations. Maximum drought quantities determined using SPI and EDI, with average data length of 125 years, have been mapped by spline interpolation technique. Furthermore, average drought parameters for each of the SPIs and EDI have been investigated and spatial distributions of drought quantities have been exhibited. In the study area, SPIs based on different time scales (either short term or long term) have detected the maximum drought severity, duration, and/or intensity (at least one of the parameters) between 2013 and 2019. It has been found that south-east Australia had faced one of the most intense droughts during 2013 to 2019. It has also been found that the longest duration of drought has been in southern and eastern coasts of the study area. Generated maps based on average EDI values have depicted that the north-western and central parts of the study area have experienced the longest and strongest drought, whereas higher-intensity drought has been found to be dominating the eastern and southern parts of the study area. Higher frequency of the number of droughts has been found mostly in the east and south of the study area in terms of moderate, severe, and extreme droughts. The generated spatial maps of SPIs and EDI in this study help to identify the most drought-prone and vulnerable parts within south-east Australia. The drought maps developed for south-eastern Australia by this spatiotemporal analysis can be a key tool to policymakers for mitigation, risk assessment, and drought preparedness planning.