Monsoonal Rainfall Time Series (1901–2002) Analysis of Uttarakhand, India

Uttarakhand is mostly a hilly state, which is located at the foothills of the Himalayan mountain ranges. Monsoon is an important phenomenon, which controls the regional climate of Uttarakhand. Thus, an effort has been made to investigate the trends of monsoonal rainfall using descriptive statistical analysis, rainfall variability index (RVI) followed by frequency and trends analysis. District-wise RVI has been developed to identify the numbers of normal, dry, very dry, wet, and very wet years. Gumbel’s extreme-value distribution and Mann–Kendall test have been used for frequency and trends analysis, respectively. The results show that lesser Himalayan district at low altitude has reported with highest magnitude of monsoonal rainfall. Further, the number of wet and very wet monsoonal years has decreased during 1951–2000 as compared to 1901–2000 in the study area. Even so, interestingly, for all districts of both regions, the number of dry and very dry years surpasses the number of wet and very wet years for the last 20 years of study. The climate of Uttarakhand is significantly controlled by monsoon and analysis of monsoon rainfall for a period of 101 years (1901–2002) reveals a decreasing trend in southwest monsoon rainfall. The outcomes of this study may help water management practices and agricultural planning in Uttarakhand.