Percolation Phase Transition of Surface Air Temperature Networks under Attacks of El Nino/La Nina

In this study, sea surface air temperature over the Pacific is constructed as a network, and the influences of sea surface temperature anomaly in the tropical central eastern Pacific (El Nino/La Nina) are regarded as a kind of natural attack on the network. The results show that El Nino/La Nina leads an abrupt percolation phase transition on the climate networks from stable to unstable or metastable phase state, corresponding to the fact that the climate condition changes from normal to abnormal significantly during El Nino/La Nina. By simulating three different forms of attacks on an idealized network, including Most connected Attack (MA), Localized Attack (LA) and Random Attack (RA), we found that both MA and LA lead to stepwise phase transitions, while RA leads to a second-order phase transition. It is found that most attacks due to El Nino/La Nina are close to the combination of MA and LA, and a percolation critical threshold Pc can be estimated to determine whether the percolation phase transition happens. Therefore, the findings in this study may renew our understandings of the influence of El Nino/La Nina on climate, and further help us in better predicting the subsequent events triggered by El Nino/La Nina.