Precursors Of The El Nino Phenomenon: A Climate Network Analysis

The identification of precursors of climatic phenomena has enormous practical importance. Recent work constructs a climate network based on surface air temperature data to analyze the El Ninio phenomena. We utilize microtransitions which occur before the discontinuous percolation transition in the network as well as other network quantities to identify a set of reliable precursors of El Ninio episodes. These precursors identify 10 out of 13 El Ninio episodes occurring in the period of 1979-2018 with an average lead time of approximately 6.4 months. We also find indicators of tipping events in the data.