Temperature and rainfall trend analysis at monthly scale in Dehradun District, Uttarakhand using variance corrected mann- kendall test

The climate variability trends in temperature and precipitation have tremendous effects on many future studies. Analysing the time-series properties of climate simulation modelling simulations offers the advantages of knowing the experimental design on which models were generated. This article addresses the two methodological aspects of time series analysis. The 20th-century climatic patterns were studied for all the 12 months (January- December) period separately. Our results show that there was a statistically significant change in the pattern of three weather parameters viz. rainfall, T_max, T_min during 1901-2002 in Dehradun District, Uttarakhand. The monthly rainfall trend in January and August period found to be decreasing and overall average reduction in rainfall amount 7.446 mm in January and 18.87 mm in August was observed during 102 years (1901-2002) periods. The increasing linear trend was observed during March and May months. The overall average increases in rainfall amount were 6.834 mm in March and 6.528 mm in May during 102 years (1901- 2002) period. Modified MK test was applied to monthly rainfall data (mm) from January to December month period, downward linear trend (p<0.05) observed for the January and August (Tau <0) of magnitude Sen’s slope -0.073 and -0.185 and intercept 26.98 and 254.91, respectively. The key findings of this study may be helpful for planning and managing seasonal and annual studies to policymakers/ planners/agricultural field workers for advising some policies to cope with anticipated climate variability and climate change.