P2C2: Signatures of the Toba Super-eruption in Borneo Stalagmites

该奖项支持从婆罗洲北部的Gunung Mulu国家公园收集年代准确的石笋，以生成通过对火山灰和挥发物的微观尺度分析确定的高分辨率大气火山负荷的配对重建，以及作为水文气候指标的石笋三角洲氧-18同位素(Delta-18O)。大型火山喷发通过硫酸盐气溶胶的辐射效应对气候产生显著的降温作用，因此是定量数据模型间比较的主要目标。作为过去200万年来最大的一次喷发，位于印度尼西亚苏门答腊岛的托巴超级火山口在大约7.4万年前喷发时，将一层厚厚的火山灰从东非扩散到南中国海。这次喷发的气候原因因千禧年规模的突然气候变化事件而变得复杂，这一事件在时间上与喷发密切相关。数值气候模型模拟证实，TOBA这样规模的喷发将对全球气候产生重大影响，尽管其辐射影响的大小和持续时间存在重大不确定性。通过这些数据集，研究人员的目标是确定相对于指示区域水文气候影响的石笋三角洲-18O异常的托巴火山灰装载的相对时间。他们将利用现有的一套模拟大型火山喷发的模拟，将他们重建的水文气候与配备水同位素的NASA/GISS ModelE2-R的输出进行比较。斯塔格米特提供了世界许多地区非常准确、高分辨率的气候重建，但只有少数几项研究调查了它们作为火山强迫历史档案的用途。婆罗洲的石笋代表了一个机会，可以进行这种绝对年代的重建，并直接将它们与一次异常大喷发的时间范围内的水文气候重建进行比较。该奖项在气候科学方面进行了强有力的公共宣传努力，例如组织了一次关于“气候如何起作用”的公开研讨会，包括当地高中的科学课程，并为参加的人提供暑期研究实习机会，以及带头为古农木鲁石笋建立永久档案馆，以确保其他科学家获得宝贵的样本。

This award supports the collection of well-dated stalagmites from the Gunung Mulu National Park in northern Borneo to generate paired reconstructions of high resolution atmospheric volcanic loading, as determined by micro-scale analyses of volcanic ash and volatiles, and stalagmite delta oxygen-18 isotopes (delta-18O), as a proxy for hydroclimate. Large volcanic eruptions have a significant cooling effect on climate through the radiative effects of sulfate aerosols and, as such, represent key targets for a quantitative data-model inter-comparison. As the largest eruption of the last 2 million years, the Toba super-caldera, located on the island of Sumatra, Indonesia, spread a thick layer of ash from East Africa to the South China Sea when it erupted roughly 74,000 years ago. The eruption's climatic attribution is complicated by a millennial-scale abrupt climate change event that is closely associated in time with the eruption. Numerical climate model simulations confirm that an eruption of Toba's size would have had significant impacts on global climate despite significant uncertainties regarding the size and duration its radiative effects. With these datasets, the researchers aim to determine the relative timing of Toba ash loading with respect to stalagmite delta-18O anomalies indicative of regional hydroclimate impacts. They will compare their hydro-climate reconstructions with output from the water isotope-equipped NASA/GISS ModelE2-R using an existing suite of simulations forced with large volcanic eruptions.Stalagmites have provided exceptionally well-dated, high-resolution reconstructions of climate in many areas of the world, yet only a handful of studies have investigated their use as archives of volcanic forcing histories. The Borneo stalagmites represent an opportunity to pursue such absolutely-dated reconstructions and to directly compare them to reconstructions of hydro-climate across the time horizon of an exceptionally large eruption. This award carries with it strong ongoing public outreach efforts in climate science such as organizing a public symposium on "How Climate Works" involving local high school science classes and offering summer research internships to those that attend as well as spearheading an initiative to establish a permanent archive for the Gunung Mulu stalagmites to ensure access to the valuable samples for other scientists.