Unraveling the missing link of ENSO control over the Indian monsoon rainfall

Using long daily rainfall (113years) data, clear evidence of modulation of the statistics of subseasonal active and break spells of the Indian summer monsoon rainfall (ISMR) by the El Nino-Southern Oscillation (ENSO) is unraveled. We show that during the El Nino (La Nina) years, the frequency of longer break (active) spells and shorter active (break) spells increases substantially, while the frequency of shorter breaks (active) and longer active (break) spells decreases compared to ENSO neutral years. It is shown that the large-scale teleconnection through which ENSO weakens (strengthens) the ISMR through shortening (lengthening) of the length of rainy season (LRS) also creates a background for modulation of the statistics of subseasonal spells leading to a further reduction (increase) in the ISMR during El Nino (La Nina) years. Our findings indicate that the statistics of subseasonal spells is predictable, brightening the prospect of seasonal prediction of the ISMR.