Revisited Asian Monsoon Hydroclimate Response to Volcanic Eruptions

Abstract

AbstractA multiproxy study of the climatic impact after the 1815 Tambora eruption in China found substantial discrepancies among the historical documents, proxy reconstructions, and model simulations. To understand whether the discrepancies are associated with regional‐scale heterogeneous hydroclimate responses or the specialty of an individual volcanic event, we revisit the Asian monsoon hydroclimate response to volcanic eruptions over the past five centuries using an independent warm season precipitation reconstruction. The composite results show a bipolar pattern of increased precipitation over the Yangtze‐Huaihe River valley and decreased precipitation over South China after the tropical eruptions, which agree with the instrumental observations of the El Chichón and Pinatubo eruptions. We could therefore reject the latter possibility and suggest that an overall drying response in the tree‐ring‐based Monsoon Asia Drought Atlas after tropical volcanic perturbations is an oversimplified conclusion. The hydroclimate responses suggest a combined influence of weakened East Asian and South Asian summer monsoons and an intensified East Asian subtropical westerly jet stream during its southward migration. Proxy reconstructions may be biased due to the sampling coverage and data sensitivities, and a combined analysis using different proxies is critical to form a balanced view of the important relationship between volcanic radiative perturbation and monsoon hydroclimate.