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Studies of the effects of large volcanic eruptions on regional climate so far have focused mostly on temperature responses. Previous studies using proxy data suggested that coherent droughts over eastern China are associated with explosive low-latitude volcanic eruptions. Here, the authors present an investigation of the responses of summer precipitation over eastern China to large volcanic eruptions through analyzing a 1000-yr global climate model simulation driven by natural and anthropogenic forcing. Superposed epoch analyses of 18 cases of large volcanic eruption indicate that summer precipitation over eastern China significantly decreases in the eruption year and the year after. Model simulation suggests that this reduction of summer precipitation over eastern China can be attributed to a weakening of summer monsoon and a decrease of moisture vapor over tropical oceans caused by large volcanic eruptions. [ABSTRACT FROM AUTHOR]

Abstract: Climate change during the last millennium is simulated using fully coupled three-dimensional model CCSM 2.0.1. The model is driven by the natural and anthropogenic forcings. Simulated temperatures over the whole of China and over the Eastern part of China, from combined forcing correlate to some extend with the proxy data, while simulated precipitation in East China (East of 105°E, 25–40°N) and the middle and lower Yangtze River Valley (106–122°E, 26–34°N) shows some similarities with the reconstructions in some periods of time. Both simulated and reconstructed temperature anomalies indicate that the 20th century warming is anomalous in a long-term context. The model indicates that the wet and dry conditions appear alternately in the Medieval Warm Period over eastern China. Dry conditions dominate in the Little Ice Age, whereas wet conditions exist since 1890. The correlation of precipitation between simulated and reconstructed is better in the middle and lower Yangtze River Valley than in East China, especially before 1850. Regional differences are present in East China during the past thousand years and there are obviously no fixed modes of climate changes (warm–wet, cold–wet, warm–dry or cold–dry). The climate change over eastern China is affected by external factors and internal climate process. The changes of temperature and precipitation over eastern China are controlled mainly by the changes of effective solar radiation and volcanic activity during the last one thousand years, while the increase of the contents of greenhouse gases plays a big role on the fast warming over the past one hundred and fifty years. [Copyright &y& Elsevier]