Bi-decadal variability excited in the coupled ocean–atmosphere system by strong tropical volcanic eruptions

Abstract

Decadal and bi-decadal climate responses to tropical strong volcanic eruptions (SVEs) are inspected in an ensemble simulation covering the last millennium based on the Max Planck Institute-Earth system model. An unprecedentedly large collection of pre-industrial SVEs (up to 45) producing a peak annual-average top-of-atmosphere radiative perturbation larger than -1.5 Wm -2 is investigated by composite analysis. Post-eruption oceanic and atmospheric anomalies coherently describe a fluctuation in the coupled ocean-atmosphere system with an average length of 20-25 years. The study provides a new physically consistent theoretical framework to interpret decadal Northern Hemisphere (NH) regional winter climates variability during the last millennium. The fluctuation particularly involves interactions between the Atlantic meridional overturning circulation and the North Atlantic gyre circulation closely linked to the state of the winter North Atlantic Oscillation. It is characterized by major distinctive details. Among them, the most prominent are: (a) a strong signal amplification in the Arctic region which allows for a sustained strengthened teleconnection between the North Pacific and the North Atlantic during the first post-eruption decade and which entails important implications from oceanic heat transport and from post-eruption sea ice dynamics, and (b) an anomalous surface winter warming emerging over the Scandinavian/Western Russian region around 10-12 years after a major eruption. The simulated long-term climate response to SVEs depends, to some extent, on background conditions. Consequently, ensemble simulations spanning different phases of background multidecadal and longer climate variability are necessary to constrain the range of possible post-eruption decadal evolution of NH regional winter climates.

An abrupt weakening of the subpolar gyre as trigger of Little Ice Age-type episodes

“…A clear response to strong volcanic eruptions was found neither in the North Atlantic climate, nor in the SPG strength (Supplementary Material in Moreno-Chamarro et al 2015). This contrasts with previous studies associating weaker SPG with periods of low solar irradiance (Moffa-Sánchez et al 2014b) or anomalous (weaker or stronger) SPG to volcanic forcing (Zhong et al 2011;Zanchettin et al 2012;Schleussner and Feulner 2013). Zanchettin et al 2013, nevertheless, showed that multiple response pathways to short-lived radiative perturbations like volcanic eruptions can exist, whose activation crucially depends on background climate conditions.…”

Ocean Response to the Pinatubo and 1259 Volcanic Eruptions

“…There have been many studies on the effect of volcanic eruptions on global climate change (Robock 2000;Stenchikov et al 1998Stenchikov et al , 2002Stenchikov et al , 2004Stenchikov et al , 2009Kirchner et al 1999;Yang and Schlesinger 2002;Shindell et al 2004;Gleckler et al 2006;Frölicher et al 2011;Mignot et al 2011;Ottera et al 2010;Zanchettin et al 2012). The studies showed that large volcanic eruptions emit sulphur gases into the stratosphere, which become sulphate aerosols.…”

“…From numerous studies on the effect of volcanic eruptions on global climate change, the change in surface response is relatively well known. Several studies have been conducted to examine the response of the ocean to volcanic eruptions (e.g., Jones et al 2005;Gleckler et al 2006;Stenchikov et al 2009;Mignot et al 2011;Ottera et al 2010;Zanchettin et al 2012). However, the effect of volcanic eruption on the ocean and its feedback on climate change remains unclear.…”

Decadal to multi-decadal scale variability of Indian summer monsoon rainfall in the coupled ocean-atmosphere-chemistry climate model SOCOL-MPIOM

“…Significance of anomalies for regimes is tested relative to the whole period AD and Cornuelle 2005; Newman 2007; Zhang et al 2007;Wu et al 2011;Frauen and Dommenget 2012;Kang et al 2014;Kayano and Capistrano 2014). These ocean modes of variability, especially AMO and ENSO, are also found to be influenced by external forcings (e.g., Meehl et al 2009;Narashima and Bhattacharyya 2010;Otterå et al 2010;Zanchettin et al 2012;Knudsen et al 2014;Pausata et al 2015). This presents a convoluted picture of the dynamics of the ISMR with ocean modes of variability and external forcings.…”