How do global temperature drivers influence each other?
A network perspective using recurrences
1 Potsdam Institute for Climate Impact Research, 14412 Potsdam, Germany
2 Department of Physics, University of Potsdam, 14476 Potsdam, Germany
3 Department of Physics, Humboldt University Berlin, 12489 Berlin, Germany
4 Institute for Complex Systems and Mathematical Biology, University of Aberdeen, AB24 3UE Aberdeen, UK
a e-mail: email@example.com
b Former affiliation: Indian Institute of Science Education and Research, Pune 411021, India.
Revised: 3 May 2013
Published online: 11 July 2013
We investigate a network of influences connected to global mean temperature. Considering various climatic factors known to influence global mean temperature, we evaluate not only the impacts of these factors on temperature but also the directed dependencies among the factors themselves. Based on an existing recurrence-based connectivity measure, we propose a new and more general measure that quantifies the level of dependence between two time series based on joint recurrences at a chosen time delay. The measures estimated in the analysis are tested for statistical significance using twin surrogates. We find, in accordance with earlier studies, the major drivers for global mean temperature to be greenhouse gases, ENSO, volcanic activity, and solar irradiance. We further uncover a feedback between temperature and ENSO. Our results demonstrate the need to involve multiple, delayed interactions within the drivers of temperature in order to develop a more thorough picture of global temperature variations.
© EDP Sciences, Springer-Verlag, 2013