Temporal Rainfall Variabilityand Its Correlation with Temperature over Ranchi, Jharkhand

Abstract

The extent to which rainfall amount varies across an area (spatial) or through time (temporal) is an important characteristic to determine the climate of an area. The discipline that covers this area in Meteorology/Climatology is known as “Rainfall variability”. It is of two types: Areal (Spatial) and Temporal. The temporal variability of rainfall means variation of rainfall as time varies but the area of the location remains the same. The temporal variability of rainfall of a place helps in knowing the rainfall variability with time. Rainfall variability plays an important role in understanding climate change. In this fast growing world, urbanization and industrialization has led to the problem of global warming. As a result of this, there has been a drift rise in temperature. The present research work was taken over to analyze the temporal trend of Rainfall over Ranchi during 1975-2017 and to study its correlation with temperature over Ranchi, Jharkhand during 1975-2009. To analyze the trend in rainfall over Ranchi, rainfall data from 1975-2017 was studied. The annual rainfall ranged from a minimum of 734.6 mm to a highest of 1771.335 mm. The mean, median, coefficient of variance and standard deviation was also found on the monthly, seasonal and annual basis. Through time series graphs of rainfall, a positive trend is detected in summer season while annual, winter and southwest monsoon rainfall appeared as a negative trend. On the other hand, by utilizing non-parametric tests such as Mann-Kendall trend test and Sen Slope, it was found that there was no significant trend at 95% confidence limit in any case. Through the study, it was found that there is a significant correlation of rainfall with temperature over the years 1975-2009. Although it was found to be negative in Summer, Monsoon and Annual data, whereas there was a positive correlation between rainfall and temperature during the winter season.