Climatic Aftermath of the 1815 Tambora Eruption in China

The 1815 eruption of the Tambora volcano led to the ＂Year without a Summer＂ and caused serious crop failure and famines in 1816 across Europe and North America. However, few reports are available on Tambora＇s influence in China despite the region＇s susceptibility to monsoonal volcanic perturbation. This study presents a systemic analysis of the climatic and related social responses to the Tambora perturbation in China, by using two independent lines of proxy records and projecting the responses on top of the impacts averaged over all tropical eruptions of the past mil- lennium. Both the tree ring and Chinese documentary proxies show that Tambora induced a cold excursion, which caused severe frost damage, snow and ice accumulations that are uncommonly seen in southern China. Cold temper- ature tends to cause drought by suppressing evaporation and monsoonal circulation- a hydroclimate response that is evident in the tree-ring-based Monsoon Asia Drought Atlas but largely missing in a multiproxy precipitation recon- struction. Historical records of drought, flood, frost, and famine also show fairly mild responses outside southern China, which may be partially due to the insensitivity of documentary records to the Tambora-induced perturbation, or the cold background climate set up by the low solar insolation of the coincident Dalton Minimum and a preceding unknown eruption in 1809. The results presented here provide new insights into the spatial extent and characteristics of the Tambora perturbation, by providing a systematic evaluation of the climatic aftermath in China in parallel to that in Europe and North America. They also argue for the integral use of multiple proxies from different regions of the world to gain a better understanding of the climatic impacts for individual volcanic eruptions.

Enhanced precipitation responses over the Tibetan Plateau following future Tambora-size volcanic eruption

Hydroclimate over the Tibetan Plateau(TP)notably influences the eco-environment of the Northern Hemisphere.Given its high elevation and complex topography,the climate in the TP shows a high sensitivity to anthropogenic warming and volcanic-induced cooling.The mechanism by which a future volcanic or similar radiative perturbation affects precipitation in the TP under an anthropogenic warming climate must be addressed not only to enable regional adaptation but deepen our understanding of how a climate system evolves under such a dual force.Here,based on the Community Earth System Model version 1.2 and ensemble simulations under pre-industrial and RCP8.5 scenarios,we showed that a Tambora-sized volcanic perturbation led to severe rainfall reduction over the south TP in the following summer(June-August).Evaporation response accounted for a minor and relatively constant share of precipitation reduction following the Clausius-Clapeyron scaling,whereas dynamic processes triggered an El Nino-like response in the eastern equatorial Pacific,which suppressed the Walker and Hadley circulation and contributed to drying anomalies.Global warming renders the post-Tambora hydroclimate responses with 30%higher severity as a result of the increased climatological moisture content and intensified El Nino response,which enhanced hydroclimate sensitivity and attenuated monsoon circulation.The results illustrate the amplification effect of global warming on the plateau's hydroclimate responses to external forcings,which may add another layer of uncertainty on climate adaptation in this already complex region.

坦博拉火山大喷发之谜--来自西藏榴辉岩的新启示

西藏松多榴辉岩系典型的古洋壳俯冲产物。通过岩相学观察与热力学计算,证实了西藏古洋壳俯冲时经历了还原反应,俯冲洋壳中Fe^(3+)和S^(6+)等物质被还原成Fe^(2+)和S^(2-),在俯冲通道内释放出富含CO_2和H_2S的流体。后者因密度低,从俯冲通道上升至岛弧火山之下的岩浆房中,最终通过火山喷发的方式排放至大气圈。因此认为,深俯冲的印度洋洋壳在地球深部也经历了相似的还原反应,将俯冲洋壳表层的硫酸盐转变为含硫流体,再通过坦博拉火山喷发的方式释放出来。现今洋壳持续俯冲,地球深部的还原反应持续进行,新生成的含硫流体正源源不断地汇聚于岛弧火山之下的岩浆房之中,因此,未来坦博拉式火山爆发是大概率事件。