A data-driven framework for dimensionality reduction and causal inference in climate fields

TL;DR

This paper introduces a data-driven framework that reduces climate data dimensionality and infers causal relationships between regions, enabling a clearer understanding of climate variability and influence patterns at a global scale.

Contribution

The novel framework combines dimensionality reduction with causal inference using fluctuation-response formalism and a new null model, providing a rigorous, interpretable approach to climate dynamics analysis.

Findings

Successfully applied to global sea surface temperature data

Identified key regions with strong causal influence

Provided visualizations of causal link maps

Abstract

We propose a data-driven framework to simplify the description of spatiotemporal climate variability into few entities and their causal linkages. Given a high-dimensional climate field, the methodology first reduces its dimensionality into a set of regionally constrained patterns. Time-dependent causal links are then inferred in the interventional sense through the fluctuation-response formalism, as shown in Baldovin et al. (2020). These two steps allow to explore how regional climate variability can influence remote locations. To distinguish between true and spurious responses, we propose a novel analytical null model for the fluctuation-dissipation relation, therefore allowing for uncertainty estimation at a given confidence level. Finally, we select a set of metrics to summarize the results, offering a useful and simplified approach to explore climate dynamics. We showcase the methodology on the monthly sea surface temperature field at global scale. We demonstrate the usefulness of the proposed framework by studying few individual links as well as "link maps", visualizing the cumulative degree of causation between a given region and the whole system. Finally, each pattern is ranked in terms of its "causal strength", quantifying its relative ability to influence the system's dynamics. We argue that the methodology allows to explore and characterize causal relationships in high-dimensional spatiotemporal fields in a rigorous and interpretable way.