Investigation of spatio-temporal variability of meteorological drought in the Luni River Basin, Rajasthan, India

Drought is one of the most serious natural disasters that threaten human societies and environments in nearly every region of the world; therefore, evaluating drought is becoming increasingly important and helpful in eradicating the effects of climate change. This study investigates the spatiotemporal drought pattern over the Luni basin from 1959 to 2019. This research analyzed spatio-temporal drought status using the standardized precipitation index (SPI). The drought trends were analyzed using the Mann-Kendall (MK) test or modified MK test and graphical innovative trend analysis (ITA). The SPI result shows that 39 studied stations are subject to mild to severe drought. The MK/mMK trend test results detected only a monotonic trend of drought across different time ranges and locations within the study area, where the ITA trend test revealed that 43% of the recorded rain gauge stations experienced a non-monotonic negative trend, more than 23% of stations were experienced a monotonic positive trend and 10% non-monotonic positive trend. In addition, with the exception of some small patches of western and eastern parts, the Z statistic result did not reveal any significant trend. The results showed that the ITA approach is more consistent than the MK test and can detect monotonic and non-monotonic trends that the MK method cannot detect. This research provided evidence that drought trends can be studied using the ITA approach, and the results of this analysis would be very useful for identifying droughts to develop effective management plans.