An intrinsic pink-noise multi-decadal global climate dynamics mode

TL;DR

This paper identifies a pink-noise characteristic in multi-decadal climate variability across various data sets, suggesting an intrinsic mode that may influence global climate patterns and their response to external forcing.

Contribution

It demonstrates the presence of pink noise in multi-decadal climate data and identifies a spatial mode linked to ocean heat flux with potential resonance to greenhouse gas forcing.

Findings

Pink noise observed in 42 climate data sets on multi-decadal scales

The first EOF mode shows pink noise characteristics and ocean heat flux distribution

The pink noise mode may resonate with external greenhouse gas forcing

Abstract

Understanding multi-decadal variability is an essential goal of climate dynamics. For example, the recent phenomenon referred to as the "global warming hiatus" may reflect a coupling to an intrinsic, pre-industrial, multi-decadal variability process. Here, using a multi-fractal time series method, we demonstrate that forty-two data sets of seventy-nine proxies with global coverage exhibit pink noise characteristics on multi-decadal time scales. To quantify the persistence of this behavior, we examine high-resolution ice core and speleothem data to find pink noise in both pre- and post-industrial periods. We examine the spatial structure with Empirical Orthogonal Function (EOF) analysis of the monthly-averaged surface temperature from 1901 to 2012. The first mode clearly shows the distribution of ocean heat flux sinks located in the eastern Pacific and the Southern Ocean, and has pink noise characteristics on a multi-decadal time-scale. We hypothesize that this pink noise multi-decadal spatial mode may resonate with externally-driven greenhouse gas forcing, driving large-scale climate processes.