Spatial analysis of drought severity and magnitude using the standardized precipitation index and streamflow drought index over the Upper Indus Basin, Pakistan

摘要

Droughts are one of the multidimensional extreme events that negatively influence agriculture, water availability and food security in the World. The Upper Indus Basin (UIB) is the major river system in the world that contributes 80% of the surface water availability in Pakistan. The objective of the current study is to analyze the spatial patterns of drought severity and magnitude using the standardized precipitation index and streamflow drought index. These drought indices were used to estimate the characteristics and a variation of the droughts annual, pre-monsoon and post-monsoon seasons for the period of 1991-2017. Results revealed that the northeastern side of the Upper Indus Basin was greatly influenced by the droughts as compared to the southwestern side. The duration from 1997 to 1998 was strongly correlated with El Nino and La Nina (ENSO) in a strong way. This type of ENSO indicates the severe drought for 5 years from 1998 to 2002 in the UIB. The episode of the warm water oceans mechanism was also strengthened in 1996, 1997, 1998, 2000, 2001 and 2002 drought years. La Nina effect has been observed in the wet and cold phase during the year of 1999. The study indicated the severe SDI drought in the years of 1991 and 2001. The study also indicated that the streamflow drought index in the post-monsoon season was marked by extreme level drought magnitude at G. Habibullah (2001), Muzaffarabad (2001), Yogo (1993) and Dhok Pathan (1998). The results of the current investigation would help policymakers to introduce new types of drought risk reduction measures for drought preparedness at the regional and the national level in Pakistan. Graphic