Affiliations: India Meteorological Department, Shivajinagar,
Pune-411005, India | Department of Environmental Science, University of
Pune, Pune-411007, India
Abstract: An attempt has been made in this study to assess drought scenario in
the Vidarbha region utilizing long period (1901–1996) monsoon rainfall
(June-September) data of the region. The analysis reveals that in Vidarbha
drought may occur once in every six years. The probability of its occurrence
for the two consecutive years is hardly 2% while that for the three consecutive
years does not exist at all. During the drought years the region receives
average seasonal rainfall of 64.8 cm, 30% less than the normal rainfall, while
rainfall in the years prior to and succeeding the drought years is found to be
5–7% more than the normal rainfall. August is found to be the most
dependable month during drought years associated with El nino as well as Enso,
while September happens to be the worst month with −50% rainfall
departure during the drought years associated with El nino. In good monsoon
years, in spite of El nino, June happens to be the worst month with a rainfall
departure of −27%. Despite reasonably high inter-annual variability,
monsoon rainfall over the region has periodicities ranging from 6 to 24 years.
Of great interest are the oscillations, which approximately are analogous to
double sunspot cycle. Planners/farmers are interested to know the prospects of
seasonal rainfall as the monsoon advances, particularly so during the initial
period of the monsoon season. Study on this aspect reveals that when June
rainfall is below normal there are 37% chances that the season too will receive
below normal rainfall; this probability increases to 50% if cumulative rainfall
till July end is below normal. Cumulative rainfall till August end generally
foretells the possible seasonal rainfall pattern over the region.
Keywords: Drought, El nino, seasonal rainfall pattern, Vidarbha region
