open access publication

Article, 2024

Impact of volcanic eruptions on CMIP6 decadal predictions: a multi-model analysis

Earth System Dynamics, ISSN 2190-4987, 2190-4979, Volume 15, 2, Pages 501-525, 10.5194/esd-15-501-2024

Contributors

Bilbao, Roberto A F 0000-0003-0729-4980 (Corresponding author) [1] Ortega, Pablo 0000-0002-4135-9621 [1] Swingedouw, Didier 0000-0002-0583-0850 [2] Hermanson, Leon 0000-0002-1062-6731 [3] Athanasiadis, Panos J 0000-0003-1249-6624 [4] Eade, Rosie 0000-0002-3566-4232 [3] Devilliers, Marion 0000-0002-3929-2747 [5] Doblas-Reyes, Francisco Javier 0000-0002-6622-4280 [1] [6] Dunstone, Nick J 0000-0001-6859-6814 [3] Ho, An-Chi 0000-0002-4182-5258 [1] Merryfield, William J [7] Mignot, Juliette 0000-0002-4894-898X [8] Nicolì, Dario 0000-0001-5890-9346 [4] Samsó, Margarida 0000-0003-2868-2755 [1] Sospedra-Alfonso, Reinel 0000-0002-4472-5607 [7] Wu, Xian 0000-0001-8117-6603 [9] Yeager, Stephen Gerald [10]

Affiliations

  1. [1] Barcelona Supercomputing Center
  2. [NORA names: Spain; Europe, EU; OECD];
  3. [2] French National Centre for Scientific Research
  4. [NORA names: France; Europe, EU; OECD];
  5. [3] Predictability Research Group, MetOffice, Exeter, UK
  6. [NORA names: United Kingdom; Europe, Non-EU; OECD];
  7. [4] Climate Simulations and Predictions Division, Centro Euro-Mediterraneo sui Cambiamenti, Climatici (CMCC), Bologna, Italy
  8. [NORA names: Italy; Europe, EU; OECD];
  9. [5] Danish Meteorological Institute
  10. [NORA names: DMI Danish Meteorological Institute; Governmental Institutions; Denmark; Europe, EU; Nordic; OECD];

Abstract

Abstract. In recent decades, three major volcanic eruptions of different intensity have occurred (Mount Agung in 1963, El Chichón in 1982 and Mount Pinatubo in 1991), with reported climate impacts on seasonal to decadal timescales that could have been potentially predicted with accurate and timely estimates of the associated stratospheric aerosol loads. The Decadal Climate Prediction Project component C (DCPP-C) includes a protocol to investigate the impact of volcanic aerosols on the climate experienced during the years that followed those eruptions through the use of decadal predictions. The interest of conducting this exercise with climate predictions is that, thanks to the initialisation, they start from the observed climate conditions at the time of the eruptions, which helps to disentangle the climatic changes due to the initial conditions and internal variability from the volcanic forcing. The protocol consists of repeating the retrospective predictions that are initialised just before the last three major volcanic eruptions but without the inclusion of their volcanic forcing, which are then compared with the baseline predictions to disentangle the simulated volcanic effects upon climate. We present the results from six Coupled Model Intercomparison Project Phase 6 (CMIP6) decadal prediction systems. These systems show strong agreement in predicting the well-known post-volcanic radiative effects following the three eruptions, which induce a long-lasting cooling in the ocean. Furthermore, the multi-model multi-eruption composite is consistent with previous work reporting an acceleration of the Northern Hemisphere polar vortex and the development of El Niño conditions the first year after the eruption, followed by a strengthening of the Atlantic Meridional Overturning Circulation the subsequent years. Our analysis reveals that all these dynamical responses are both model- and eruption-dependent. A novel aspect of this study is that we also assess whether the volcanic forcing improves the realism of the predictions. Comparing the predicted surface temperature anomalies in the two sets of hindcasts (with and without volcanic forcing) with observations we show that, overall, including the volcanic forcing results in better predictions. The volcanic forcing is found to be particularly relevant for reproducing the observed sea surface temperature (SST) variability in the North Atlantic Ocean following the 1991 eruption of Pinatubo.

Keywords

Atlantic, Atlantic Meridional Overturning Circulation, Atlantic Ocean, Coupled Model Intercomparison Project Phase 6, El Nino, Meridional Overturning Circulation, Nino, North, North Atlantic Ocean, Overturning Circulation, Phase 6, Pinatubo, acceleration, aerosol, aerosol loading, analysis, anomalies, aspects, baseline, baseline predictions, changes, circulation, climate, climate change, climate impacts, climate predictions, climatic conditions, component C, composition, conditions, consistent with previous work, cooling, coupling, decadal predictions, decadal timescales, decades, development, dynamic response, effect, eruption, eruption of Pinatubo, estimation, exercise, force, force results, hindcast, impact, impact of volcanic aerosols, impact of volcanic eruptions, inclusion, initial conditions, initialisation, intensity, internal variables, load, model, multi-model analysis, northern hemisphere polar vortex, novel aspect, observations, observed climate conditions, observed sea surface temperature, ocean, polar vortex, prediction, previous work, protocol, radiation effects, realism, response, results, retrospective predictions, sea surface temperature, stratospheric aerosol loading, strengthening, study, surface temperature, surface temperature anomalies, system, temperature, temperature anomalies, time, timescales, variables, volcanic aerosols, volcanic effects, volcanic eruptions, volcanic forcing, vortex, work, years

Funders

  • European Research Council
  • Government of Catalonia
  • Ministry of Economy, Industry and Competitiveness
  • European Commission
  • Office of Biological and Environmental Research

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