Understanding and assessing the spatial characteristics of drought hazard in the state of Rajasthan

Abstract

Climate change has exposed the world to more frequent and prolonged occurrences of extreme and diverse events. The frequency of extreme dry events, such as drought, is on the rise, significantly impacting various socioeconomic sectors, especially in arid regions like the Indian state of Rajasthan. These changes in drought occurrence have far-reaching consequences on the socioeconomic landscape. In this study, using the Standardized Precipitation Index (SPI) we examined meteorological drought characteristics in the state of Rajasthan to identify three categories of drought events (mild, moderate, and severe) at multi-temporal scales (i.e., 3-month, 6-month, and 12-month). For this monthly rainfall data for a period of 34 years (1988-2021) are used from 165 well-spread meteorological stations across the state. The results of the study reveal that the state of Rajasthan experienced frequent milder drought events, followed by moderate and extreme drought events during the study period. Our findings indicate that severe drought events predominantly occur during the months of July- September whereas moderate and mild droughts are more commonly observed during April – June. After analyzing the frequency, intensity, and duration of drought events, we created drought hazard maps at different temporal scales. The results obtained from the SPI12 hazard mapping indicate that the northern and northwestern regions, covering the districts of Jaisalmer, Jodhpur, Jaipur, Sikar, western Bikaner, Hanumangarh, and Ganganagar are the most drought-prone areas within the state. To analyze the trends in rainfall and drought events across different time scales, we conducted the nonparametric Mann-Kendall (MK) test. The results of the MK test indicated that out of the 165 stations examined, 130 stations (26 significant, p < 0.001) exhibit an increasing trend in mean annual rainfall. Conversely, 34 stations (2 significant, p < 0.001) demonstrated a decreasing trend in rainfall. In response to the increasing rainfall, drought events are found to decrease over the study period even at a shorter temporal scale (i.e., 3month-SPI) at most of the stations. Policymakers and stakeholders could benefit from the long-term drought hazard map in identifying drought-prone regions and formulating policies and programs to promote water conservation and enhance drought preparedness in the state.