Paleoatmospheric Krypton and Xenon Abundances from Trapped Air in Polar Ice as Indicators of Past Mean Ocean Temperature

Severinghaos该奖项支持一个项目，该项目旨在通过冰芯中的气泡来测量古大气中的Kr/N_2。这些测量值可能表明了过去平均海洋温度的变化。了解过去的平均海洋温度将有助于洞察深海温度的过去变化，这些变化仍然知之甚少。深海温度变化对于理解气候变化的机制很重要。氪在水中高度溶解，其溶解度随温度而变化，水温越低，其溶解度越高。因此，上一次冰川时期较冷的海洋会比今天的海洋容纳更多的氪。由于海洋-大气系统中的氪总量是恒定的，因此冰川海洋中氪库存的增加应该会导致大气中氪库存的减少。这项工作的主要目标是发展使用Kr/N_2作为古海洋平均温度的指标。这将涉及改进Kr/N_2测量本身的分析技术，以及测量Vostok和GISP2冰芯中最后一次冰盛期(LGM)和晚全新世以来冰中气泡中的Kr/N_2。这提供了对末次盛冰期平均海洋温度变化的估计，并允许比较先前在末次盛冰期期间对深海温度的估计。Vostok冰芯是这方面的理想之选，因为它没有熔化层，这会影响氪和氙气的信号。另一个目标是提高Xe/N2测量的精度，它可以作为海洋温度变化的第二个独立指标。这一过渡期间的平均海洋温度时间序列可能有助于解释这些观测结果。此外，拟议的工作将测量GISP2冰芯中海洋同位素阶段(MIS3)的Kr/N2。了解管理信息系统3期间过去的海洋温度将有助于限制这段时间内的海平面估计。拟议工作的更广泛影响是：它将首次估计过去平均海洋温度变化的范围和时间。这将有助于限制先前提出的涉及深海温度大幅变化的气候变化机制。该项目还将支持研究生的教育。国际和平协会就气候变化向媒体和公众进行采访和演讲，这项工作将加强这些外展活动。最后，这项工作将在国际极地年(IPY)期间进行，并将强调极地区域对于了解全球大气和海洋系统的独特重要性。

0538630SeveringhausThis award supports a project to produce the first record of Kr/N2 in the paleo-atmosphere as measured in air bubbles trapped in ice cores. These measurements may be indicative of past variations in mean ocean temperature. Knowing the mean ocean temperature in the past will give insight into past variations in deep ocean temperature, which remain poorly understood. Deep ocean temperature variations are important for understanding the mechanisms of climate change. Krypton is highly soluble in water, and its solubility varies with temperature, with higher solubilities at colder water temperatures. A colder ocean during the last glacial period would therefore hold more krypton than today's ocean. Because the total amount of krypton in the ocean-atmosphere system is constant, the increase in the krypton inventory in the glacial ocean should cause a resultant decrease in the atmospheric inventory of krypton. The primary goal of this work is to develop the use of Kr/N2 as an indicator of paleo-oceanic mean temperature. This will involve improving the analytical technique for the Kr/N2 measurement itself, and measuring the Kr/N2 in air bubbles in ice from the last glacial maximum (LGM) and the late Holocene in the Vostok and GISP2 ice cores. This provides an estimate of LGM mean ocean temperature change, and allows for a comparison between previous estimates of deep ocean temperature during the LGM. The Vostok ice core is ideal for this purpose because of the absence of melt layers, which compromise the krypton and xenon signal. Another goal is to improve precision on the Xe/N2 measurement, which could serve as a second, independent proxy of ocean temperature change. A mean ocean temperature time series during this transition may help to explain these observations. Additionally, the proposed work will measure the Kr/N2 from marine isotope stage (MIS) 3 in the GISP2 ice core. Knowing the past ocean temperature during MIS 3 will help to constrain sea level estimates during this time period. The broader impacts of the proposed work: are that it will provide the first estimate of the extent and timing of mean ocean temperature change in the past. This will help to constrain previously proposed mechanisms of climate change involving large changes in deep ocean temperature. This project will also support the education of a graduate student. The PI gives interviews and talks to the media and public about climate change, and the work will enhance these outreach activities. Finally, the work will occur during the International Polar Year (IPY), and will underscore the unique importance of the polar regions for understanding the global atmosphere and ocean system.