LAUSR

The present work reports a study on the behavior of the time series of rainfall during the summer monsoon (June–September) in northeast India. It has been observed through hypothesis testing that although a normal distribution fits the time series, no persistence forecast is possible as indicated by the low value of the Lag-1 autocorrelation coefficient (0.041). A linear regression over time is not a good fit. Subsequently, the intrinsic behavior of the time series has been explored through Hurst exponent (H) computed using rescaled range analysis. The value of the Hurst exponent is in the range of 0 < H < 0.5, and from this range, it could be understood that long-term switching is expected to exist between high and low values in adjacent pairs. However, when the Hurst exponent value is being low, the summer monsoon rainfall over northeast India has been thought of as characterized by volatility and roughness. Finally, the connectivity of the El Niño-Southern Oscillation (ENSO) to the Indian summer monsoon rainfall has been briefly discussed in light of the long-term behavior.