Drought hazard depending on elevation and precipitation in Lorestan, Iran

Drought is a type of destructive hydro-climatic disaster that has a significant impact on agriculture and natural resources. Meteorological drought features, including severity, duration, and peak, exhibit various patterns in different climatic regions and geographical conditions. Several indices have been developed to assess the drought potential of different areas across the world, among which the drought hazard index (DHI) is one of the most commonly employed for semi-arid and the flat regions. This study investigates the effects of the elevation and precipitation on DHI, which has received little attention in previous studies. For this purpose, DHIs were computed for 15 stations located at different elevations of the study area over 31 years by considering the occurrence of various drought classes with different weights. The results showed that the elevation and mean precipitation both have inverse effects on the DHI in the study area, which means that the DHI increases when the elevation and mean precipitation are low. The results of the estimation of the DHI for three different periods (i.e., 6, 9, and 12 months) revealed that a 9-month period is optimum for DHI estimations in terms of the reliability of the results.