Berlin 2015 – scientific program
DY 17.7: Talk
Tuesday, March 17, 2015, 11:15–11:30, BH-N 333
A new typology of El Niño and La Niña phases based on evolving climate networks — •Marc Wiedermann1,2, Alexander Radebach2,3, Reik V. Donner1, Jonathan F. Donges1,4, and Jürgen Kurths1,2 — 1Potsdam Insitute for Climate Impact Research, Germany — 2Humboldt University, Berlin, Germany — 3Mercator Research Institute on Global Commons and Climate Change, Berlin, Germany — 4Stockholm Resilience Centre, Stockholm University, Sweden
The El Niño Southern Oscillation (ENSO) has a large impact on the global climate system. Its variability can roughly be categorized into El Niño (anomalously warm), La Niña (anomalously cold) and normal periods. Recently, it has been suggested that El Niño and La Niña can be further discriminated into two different types. However, no formal criterion for this distinction has been introduced so far. Here, we use evolving climate networks from daily surface air temperature fields and investigate the time-evolution of their structural properties. During certain El Niño and La Niña periods global network measures show distinct peaks indicating an induced reorganization of the global climate system. For ENSO events without such reorganization, we find substantially different spatial patterns of degree and other local measures than for the other events. This observation can be attributed to the general signature of normal vs. anomalous ENSO events. In this spirit, characteristics involved in the assessment of evolving climate networks allow to detect structural similarities between different ENSO periods and systematically categorize these different stages.