Impacts of El Nino-Southern Oscillation on tropical precipitation via triggering anomaly water vapour transport from ocean to land

Atmospheric water vapour transport is one of the most active components of the hydrological cycle, which shows great effects on the regional climate variability, while it is largely affected by the large-scale circulation systems. El Nino-Southern Oscillation (ENSO) shows a remarkable influence on the atmospheric water circulation via disrupting the normal/regular water vapour transport processes, producing the anomaly water vapour fluxes input from ocean to land (Q(net)), and leading to regional precipitation anomalies. However, their quantitative impact has not been fully studied. This study quantified the effect of ENSO on the water vapour transport from ocean to land and identified its impact on tropical precipitation anomalies. The results showed that the global detrended Q(net) displayed a significantly negative correlation with the strength of ENSO. The notable impact of ENSO on Q(net) was largely affected by the different patterns of the atmospheric moisture circulation during El Nino and La Nina and was responsible for the change of the spatial distribution of precipitation over the Tropics. El Nino reduced precipitation over the Malay Archipelago and increased precipitation over south China, especially in boreal winter, while La Nina enhanced precipitation over the Malay Archipelago. This study identified the impacts of ENSO on the circulation and water vapour transport process and improved our understanding of the influencing mechanism of ENSO on regional precipitation anomalies, which has important significance on regional water resource management and disaster risk assessment, especially as the extreme climate events have become increasingly frequent.