Analysis of temporal trend of rainfall, temperature and extreme events over Jharkhand

This study investigates the temporal variability of rainfall, temperature and extreme events over Jharkhand. The seasonal rainfall variability is examined for the period 1901 to 2018 and extreme rainfall events and temperature variability is examined for three stations (Ranchi, Jamshedpur and Daltonganj) for the period 1986 to 2018. To examine the temporal trend, a widely used non parametric Mann-Kendall test applied at 95% confidence level. The trend analysis indicated that the seasonal rainfall significantly decreased for the study period at the rate of 13mm per decade over Jharkhand. The average annual maximum temperature shows significantly increasing trend at the rate of 0.58 degrees C, 0.47 degrees C and 0.29 degrees C per decade at Ranchi, Jamshedpur and Daltonganj respectively. Similarly, the average annual minimum temperature also shows significantly increasing trend at the rate of 0.46 degrees C per decade at Ranchi and Jamshedpur and the increasing trend is 0.13 degrees C per decade for Daltonganj.The analysis reveals that the change in rainfall over the period of time is directly associated with number of rainy days, heavy rainy days and extreme rainfall events. The decreasing (increasing) trend of annual rainfall over Ranchi (Jamshedpur) is associated with decreasing (increasing) annual number of rainy days and heavy rainy days. No significant trend is observed in annual rainfall, extreme rainfall and heavy rainy days over Daltonganj. Result also shows that the increase in the temperature over the period is associated with the increase in number of heat wave days and decrease in cold wave days. All three stations have increasing trend of heat wave and severe heat wave and decreasing trend of cold wave and severe cold wave days.