Driven Methods for Granger Causality and Contemporaneous Causality with Non-Linear Corrections : Climate Teleconnection Mechanisms
We describe a unification of old and recent ideas for formulating graphical models to explain time series data, including Granger causality, semi-automated search procedures for graphical causal models, modeling of contemporaneous influences in times series, and heuristic generalized additive model corrections to linear models. We illustrate the procedures by finding a structure of exogenous variables and mediating variables among time series of remote geospatial indices of ocean surface temperatures and pressures. The analysis agrees with known exogenous drivers of the indices, not assumed in the analysis. Automated search applied to the residuals after regressing each series on its lags and the lags of its Granger causes yields a graphical model of “comtemporaneous” causal relations identical with the qualitative graphical relations from the time series. A similar analysis produces reasonable results when applied to candidate climate indices obtained by a clustering method from sea surface temperature and sea level pressure data. 1. Institute for Human and Machine Cognition, University of West Florida 2. Department of Philosophy, Carnegie Mellon University Research for this paper was supported by the National Aeronautics and Space Administration Intelligent Data Understanding program and the Office of Naval Research. We thank Drs. Rama Nemani, Alessio Monetta and Peter Spirtes for valuable assistance.