Analysis of structural differences and causes of ENSO temperature network

Abstract

Based on the global surface temperature data, the global temperature correlation networks corresponding to El Niño and La Niña events are constructed respectively, and the differences in their effects on the network topological structure properties are analyzed. The results show that compared with the La Niña temperature network, the correlation between grid temperature series in El Niño temperature network is weakened, and the connectivity of the network is significantly reduced, especially in the tropical region and the southern temperate region. The network connectivity degree of equatorial eastern Pacific, equatorial western Pacific, equatorial Indian Ocean and equatorial Atlantic Ocean are relatively large, and the decrease in El Niño network is notable. They are also the four key regions leading to the differences of the structural characteristics of the two types of network. On this basis, the reason for the difference between the two types of network characteristics is preliminarily discussed. With the increase of SST in Niño3.4 region, the SST in equatorial eastern Pacific, equatorial Indian Ocean and other areas rise, which strengthenes outgoing long wave radiation and convection activities, and the interaction between low latitude and mid-latitude areas, and the variance of air temperature changes in the north and south temperate regions increase. As a result, the correlation between the temperature series of the four key regions and the rest of the world is weakened, therefore the connectivity of the global grid temperature network is reduced.