Volcanic Imprints in Last-Millennium Land Summer Temperatures in the Circum-North Atlantic Area

Journal Article · 07 August 2023 · Journal of Climate

DOI: https://doi.org/10.1175/jcli-d-23-0107.s1 · OSTI ID:2424662

Wang, Feng ^[1]; Arseneault, Dominique ^[2]; Boucher, Etienne ^[3]; Gennaretti, Fabio ^[4]; Lapointe, Francios ^[5]; Yu, Shulong ^[6]; Francus, Pierre ^[1]

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1. National Institute of Scientific Research (Canada); GEOTOP Research Centre in the Dynamics of the Earth System (Canada)
2. Université du Québec à Rimousk (UQAR) (Canada); Laval University (Canada)
3. GEOTOP Research Centre in the Dynamics of the Earth System (Canada); Laval University (Canada); Univ. of Quebec à Montréal (Canada)
4. Univ. of Quebec en Abitibi-Témiscamingue (Canada)
5. Univ. of Massachusetts, Amherst, MA (United States)
6. China Meteorological Administration (China)

Summer cooling is one of the most direct consequences of explosive volcanic eruptions that can affect ecosystems and human societies. Recent studies revealed a multiyear cooling impact on hemispheric and global summer temperatures after tropical eruptions, yet the volcanic responses appear to vary on regional scales. Here, in this work, we revisit volcano-induced summer cooling in eastern Canada and northern and central Europe by applying superposed epoch analysis on CMIP6-PMIP4 simulations and millennial temperature reconstructions based on tree-ring density. We then examine potential causes modulating region-specific volcanic impact. While confirming that, on average, tropical eruptions over the last millennium have induced a longer cooling (>4 yr) than eruptions from extratropical Northern Hemisphere in all three North Atlantic regions, we show that the peak magnitude of cooling is stronger in eastern Canada. We also find that the detected volcanic temperature anomalies can be strongly affected by the selection and number of volcanic events and nonvolcanic signals embedded in the climate time series. This study highlights the risks of using highly noisy proxy records to investigate volcanic impacts, especially in regions with strong unforced climate variability. The CMIP6-PMIP4 simulations generally agree with the three reconstructions on the average response to tropical eruptions, but their performance is poorer regarding the production of significant cooling after extratropical eruptions. Our results further suggest that the particular sensitivity to tropical eruptions in eastern Canada is likely related to increased sea ice surrounding Quebec–Labrador associated with the positive Arctic Oscillation and North Atlantic Oscillation formed during the first posteruption winter.

• Research Organization: Univ. of Massachusetts, Amherst, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• OSTI ID: 2424662
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Journal Issue: 17 Vol. 36; ISSN 0894-8755
• Publisher: American Meteorological SocietyCopyright Statement
• Country of Publication: United States
• Language: English