Climatic Variability of Rainfall and Cyclonic Systems over Vidarbha: New Trends

Abstract

The present study has been carried out to identify variability and trends between cyclonic systems and annual rainfall in Part-I (1961-1990) & Part-II (1991-2020) of the meteorological data from Vidarbha, India. A decreasing trend has been seen in the number of cyclonic systems formed over the Bay of Bengal and the Arabian Sea (-0.207 no. of CS /year and -0.118/year respectively) during Part I, whereas, there has been seen increasing trend in the number of cyclonic systems formed over the Bay of Bengal and the Arabian Sea (at the rate 0.042 no. of CS /year and 0.141/year respectively) in Part II. Consequently, it is also seen that rainfall trends have been increasing over east Vidarbha. There is a favourable influence of the formation of cyclonic systems on annual rainfall over Vidarbha and improvement in annual rainfall (at the rate of 1.27 mm/year) over East Vidarbha, but slightly decreasing trends (-0.033 mm/year) is seen over west Vidarbha. The impact of the increasing frequency of cyclonic systems over Arabian Sea has been seen over the rainfall of east Vidarbha during the year 1961-1990.

 It is observed that trend of the frequency of the formation of cyclonic systems has been decreasing during 1982-2011 and increasing from 2012 onward. No definite trend in annual rainfall was seen during 1961-1983 and 1984 onward, it has been shown an increase over East Vidarbha and annual rainfall has been decreasing during 1988-2003 and 2003 onward no definite trend has been seen over West Vidarbha. There exists a high value of the coefficient of variance between Part-I and Part-II of annual rainfall and cyclonic systems, which indicates good variability for annual rainfall between Part I and Part II of annual rainfall and cyclonic systems.  The outcomes of the study would be useful for good planning for agriculture, administration, forecasters and all concerned.