The Effect of Explosive Tropical Volcanism on ENSO

McGregor, Shayne; Timmermann, Axel

doi:10.1175/2010jcli3990.1

Cited by 116 publications

(133 citation statements)

References 37 publications

(54 reference statements)

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“…While Mann et al (2005) and Emile-Geay et al (2007), using the same model, find that larger changes in solar irradiance can influence ENSO variability via changes in the background state of the tropical Pacific, such changes are not supported by current reconstructions of solar irradiance over the past 1500 years (Schmidt et al 2012). The lack of any detectable volcanic influence on ENSO variability is also consistent with other modeling studies, which find that volcanoes alter the probabilities of El Niño and La Niña events occurring in the immediate aftermath of an eruption but otherwise have no lasting impact (Mann et al 2005;Emile-Geay et al 2008;McGregor and Timmermann 2011).…”

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confidence: 60%

Paleoclimate Data–Model Comparison and the Role of Climate Forcings over the Past 1500 Years*

et al. 2013

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Ommen, T. D. (2013). Paleoclimate data-model comparison and the role of climate forcings over the past 1500 years. Journal of Climate, 26 (18), 6915-6936. Paleoclimate data-model comparison and the role of climate forcings over the past 1500 years AbstractThe past 1500 years provide a valuable opportunity to study the response of the climate system to external forcings. However, the integration of paleoclimate proxies with climate modeling is critical to improving the understanding of climate dynamics. In this paper, a climate system model and proxy records are therefore used to study the role of natural and anthropogenic forcings in driving the global climate. The inverse and forward approaches to paleoclimate data-model comparison are applied, and sources of uncertainty are identified and discussed. In the first of two case studies, the climate model simulations are compared with multiproxy temperature reconstructions. Robust solar and volcanic signals are detected in Southern Hemisphere temperatures, with a possible volcanic signal detected in the Northern Hemisphere. The anthropogenic signal dominates during the industrial period. It is also found that seasonal and geographical biases may cause multiproxy reconstructions to overestimate the magnitude of the long-term preindustrial cooling trend. In the second case study, the model simulations are compared with a coral δ18O record from the central Pacific Ocean. It is found that greenhouse gases, solar irradiance, and volcanic eruptions all influence the mean state of the central Pacific, but there is no evidence that natural or anthropogenic forcings have any systematic impact on El Niño-Southern Oscillation. The proxy climate relationship is found to change over time, challenging the assumption of stationarity that underlies the interpretation of paleoclimate proxies. These case studies demonstrate the value of paleoclimate data-model comparison but also highlight the limitations of current techniques and demonstrate the need to develop alternative approaches. ABSTRACTThe past 1500 years provide a valuable opportunity to study the response of the climate system to external forcings. However, the integration of paleoclimate proxies with climate modeling is critical to improving the understanding of climate dynamics. In this paper, a climate system model and proxy records are therefore used to study the role of natural and anthropogenic forcings in driving the global climate. The inverse and forward approaches to paleoclimate data-model comparison are applied, and sources of uncertainty are identified and discussed. In the first of two case studies, the climate model simulations are compared with multiproxy temperature reconstructions. Robust solar and volcanic signals are detected in Southern Hemisphere temperatures, with a possible volcanic signal detected in the Northern Hemisphere. The anthropogenic signal dominates during the industrial period. It is also found that seasonal and geographical biases may cause multiproxy reconstructions to overestim...

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confidence: 60%

Paleoclimate Data–Model Comparison and the Role of Climate Forcings over the Past 1500 Years*

et al. 2013

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“…McGregor and Timmermann (2011) and reported an enhanced probability of La Niña events occurring in the immediate years after a volcanic eruption, rather than El Niño, while several other studies (Self et al, 1997;Robock, 2000;Ding et al, 2014) found no relationship between ENSO and volcanic forcing. Robock (2000) argued that both El Chichon and Pinatubo reached their peak forcing after the initiation of El Niño events, indicating a coincidental relationship.…”

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confidence: 93%

Assessing the impact of large volcanic eruptions of the last millennium (850–1850 CE) on Australian rainfall regimes

et al. 2018

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Abstract. Explosive volcanism is an important natural climate forcing, impacting global surface temperatures and regional precipitation. Although previous studies have investigated aspects of the impact of tropical volcanism on various ocean-atmosphere systems and regional climate regimes, volcanic eruptions remain a poorly understood climate forcing and climatic responses are not well constrained. In this study, volcanic eruptions are explored in particular reference to Australian precipitation, and both the Indian Ocean Dipole (IOD) and El Niño-Southern Oscillation (ENSO). Using nine realisations of the last millennium (LM) (850-1850 CE) with different time-evolving forcing combinations, from the NASA GISS ModelE2-R, the impact of the six largest tropical volcanic eruptions of this period are investigated. Overall, we find that volcanic aerosol forcing increased the likelihood of El Niño and positive IOD conditions for up to four years following an eruption, and resulted in positive precipitation anomalies over north-west (NW) and south-east (SE) Australia. Larger atmospheric sulfate loading during larger volcanic eruptions coincided with more persistent positive IOD and El Niño conditions, enhanced positive precipitation anomalies over NW Australia, and dampened precipitation anomalies over SE Australia.

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“…Modeling studies do not yield consistent results and show both an El Niño-like (3)(4)(5) or La Niña-like (6,7) anomalies following a tropical eruption. Recent studies have also suggested that volcanic eruptions can have a large imprint on ocean circulation, affecting the strength of the Atlantic Meridional Overturning Circulation (AMOC) (8-12) on 5-to 20-y timescales and inducing ocean heat content (OHC) anomalies (13,14) that may persist for decades.…”

mentioning

confidence: 91%

Impacts of high-latitude volcanic eruptions on ENSO and AMOC

Pausata

Chafik

Caballero

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Large volcanic eruptions can have major impacts on global climate, affecting both atmospheric and ocean circulation through changes in atmospheric chemical composition and optical properties. The residence time of volcanic aerosol from strong eruptions is roughly 2-3 y. Attention has consequently focused on their short-term impacts, whereas the long-term, ocean-mediated response has not been well studied. Most studies have focused on tropical eruptions; high-latitude eruptions have drawn less attention because their impacts are thought to be merely hemispheric rather than global. No study to date has investigated the long-term effects of high-latitude eruptions. Here, we use a climate model to show that large summer high-latitude eruptions in the Northern Hemisphere cause strong hemispheric cooling, which could induce an El Niño-like anomaly, in the equatorial Pacific during the first 8-9 mo after the start of the eruption. The hemispherically asymmetric cooling shifts the Intertropical Convergence Zone southward, triggering a weakening of the trade winds over the western and central equatorial Pacific that favors the development of an El Niño-like anomaly. In the model used here, the specified high-latitude eruption also leads to a strengthening of the Atlantic Meridional Overturning Circulation (AMOC) in the first 25 y after the eruption, followed by a weakening lasting at least 35 y. The long-lived changes in the AMOC strength also alter the variability of the El Niño-Southern Oscillation (ENSO).high-latitude volcanic eruptions | AMOC-ENSO interaction | volcanism P roxy data (1, 2) suggest that the strong reduction of surface insolation over the tropics associated with tropical volcanic eruptions may increase the likelihood of the El Niño-Southern Oscillation (ENSO) and a consequent reduction of the zonal sea surface temperature (SST) gradient along the equatorial Pacific. Modeling studies do not yield consistent results and show both an El Niño-like (3-5) or La Niña-like (6, 7) anomalies following a tropical eruption. Recent studies have also suggested that volcanic eruptions can have a large imprint on ocean circulation, affecting the strength of the Atlantic Meridional Overturning Circulation (AMOC) (8-12) on 5-to 20-y timescales and inducing ocean heat content (OHC) anomalies (13, 14) that may persist for decades. However, this slow recovery has been questioned and may be an artifact of experimental design (15). Furthermore, all previous work on the climate impact of volcanic eruptions has focused on tropical volcanoes; no studies have addressed the potential effects of high-latitude eruptions on ENSO. Here, we use a coupled atmospheric-ocean-aerosol model 17)] to identify the mechanisms by which high-latitude volcanic eruptions can impact ENSO behavior in both the short term (up to 2-3 y) and long term (approximately half-century), the latter being mediated by volcano-induced changes in ocean circulation.We simulate an extreme high-latitude multistage eruption starting on June 1st. We inject 100 Tg of SO...

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The Effect of Explosive Tropical Volcanism on ENSO

Cited by 116 publications

References 37 publications

Paleoclimate Data–Model Comparison and the Role of Climate Forcings over the Past 1500 Years*

Paleoclimate Data–Model Comparison and the Role of Climate Forcings over the Past 1500 Years*

Assessing the impact of large volcanic eruptions of the last millennium (850–1850 CE) on Australian rainfall regimes

Impacts of high-latitude volcanic eruptions on ENSO and AMOC

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