Inconsistency in the frequency of rainfall events in the Indian summer monsoon season

In global warming, India is adversely affected by weather extremes. Summer monsoon contributes about 70% of annual mean rainfall to India by mode of an ensemble of synoptic disturbances and intense events. These events bring extreme amounts of rainfall in very few days. We have studied the anomalies of rainfall events for wet days (>0 mm rainfall), dry days (=0 mm), little rainfall days (>0 to <20mm), moderate rainfall days (>= 20mm to <60mm), heavy rainfall days (>= 60 to <100mm) and very heavy rainfall days (>= 100mm) during the period, 1901-1930; 1931-1960; 1961-1990 and 1991-2015 using India Meteorological Department (IMD) rainfall data. In the present scenario, even though an extensive increase in frequency of lows forming in the Bay of Bengal is observed, only a few are intensified into depressions and above stages. Alternatively, monsoon circulation is trailing its strength; therefore extreme (heavy and very heavy rainfall) events came into existence to balance the mean rainfall activity. The rise in these events may be due to an increasing inconsistency of the strength of low-level jet, an increase of sea surface temperature over the Arabian Sea and dynamic flow of moisture supply to inland from neighbourhood seas. An increase in the frequency of extreme rainfall events is seen over Konkan & Goa, Madhya Maharashtra, Jammu & Kashmir, central Northeast India (CNEI) and west central India (WCI) in the recent years (25years) compared to previous 9 decades. Whereas, a decrease in the frequencies of little and moderate rainfall events are observed over the parts of the Western Ghats, Northeast India, WCI and CNEI. There is an increasing trend in the inconsistency of daily rainfall activity due to an increase in the frequency of extreme events in the global warming era.