Spatio-temporal Trend Analysis of Climatic Variables over Jharkhand, India

Time-series data for climatic variables of Jharkhand state, India were analyzed to assess the spatio-temporal variation and fluctuation over the study period of 118 years (1901–2018). Mann–Kendall (MK), Sequential Mann–Kendall (SQMK), and Sen’s slope tests were applied to determine the trend of precipitation, temperature maxima–minima, and Potential Evapotranspiration (PET) time-series data acquired after removal of serial autocorrelation called prewhitening. Minimum and maximum temperature revealed insignificant variation during pre-monsoon and monsoon season, while a remarkable increasing trend was observed for post-monsoon and winter season; however, increasing trend was obtained for annual maxima–minima. The average minimum temperature fluctuates with an increase of 0.59–0.41 ºC to a decrease of 0.79–0.39 ºC, whereas average maximum temperature fluctuates with an increase of 1–1.5 ºC to decrease of 0.82–0.14 ºC. Notably, decreasing trend of 1.09–2.3 mm/year was observed for precipitation during monsoon season, whereas decreasing trend of 1.2–2.4 mm/year was found for annual precipitation, and similarly for PET, significant decreasing trend of 0.0003–0.0012 mm/year was found for monsoon season and annually. However, the underlying persistence effect observed in all seasons and throughout the year for all climatic parameters resulted in the time-series with low-frequency fluctuations. SQMK method exhibits the periodic fluctuation of trends, which are more noticeable in pre-monsoon and monsoon season. An understanding of these alterations in pattern of climatic variables is important for planning and management of water resources and sustainable agriculture.