Winter warming and summer monsoon reduction after volcanic eruptions in Coupled Model Intercomparison Project 5 (CMIP5) simulations

Though previous studies have shown that state‐of‐the‐art climate models are rather imperfect in their simulations of the climate response to large volcanic eruptions, the results depend on how the analyses were done. Observations show that all recent large tropical eruptions were followed by winter warming in the first Northern Hemisphere (NH) winter after the eruption, with little such response in the second winter, yet a number of the evaluations have combined the first and second winters. We have looked at just the first winter after large eruptions since 1850 in the Coupled Model Intercomparison Project 5 historical simulations and find that most models do produce a winter warming signal, with warmer temperatures over NH continents and a stronger polar vortex in the lower stratosphere. We also examined NH summer precipitation responses in the first year after these large volcanic eruptions and find clear reductions of summer monsoon rainfall.