Collaborative Research: Constraining Late Pleistocene Tropical Climates by Dating and Modeling Former Glaciers

该奖项资助合作研究，以重建21,000年前末次冰期最大期（LGM）的气候，方法是对来自莫纳克亚山、夏威夷和夏威夷山的前晚更新世冰川进行测年和建模。吉卢韦，巴布亚新几内亚。 研究人员将研究地球热带地区的冰碛，以更好地了解气候系统对辐射强迫的敏感性。 低纬度地区接收到的过量辐射是地球气候系统的主要驱动力。 研究的总体目标是审查地球气候对行星辐射强迫的反应的一些基本物理要素，这些要素与目前有很大不同。冰川冰碛的年代测定将使用从表面巨砾取样测量的宇宙成因核素。 对于每个油田区域，从通常被认为代表LGM的冰碛物中收集的样品将通过3 He（氦）和36 Cl（氯）进行测年。 为了解决有关低纬度地区3 He的缩放和生产率的问题，该项目包括使用夏威夷放射性碳定年熔岩流进行校准。气候建模将遵循应用改进的建模策略来重建维持晚更新世热带冰川作用所需的气候变化的愿望。 具体而言，建模工作将使用一个基于物理的质量和能量平衡冰川模型，该模型已经过验证，并适用于不同地形和气候环境中的几个冰川。冰川模型考虑了地形阴影、时间和空间的变化、辐射收支的显式处理和湍流通量。 这些都是冰川质量平衡的重要控制因素。这项研究之所以重要，是因为它有可能通过提供该地区LGM冰川作用的高分辨率年表来提高我们对热带地区基本气候过程的理解，LGM是地球气候体系重要重组的时刻。 这项研究将为两个机构的研究生提供古气候研究方面的多学科教育经验。

This award funds collaborative research to reconstruct climate during the Last Glacial Maximum (LGM) at 21,000 years ago by dating and modeling former late Pleistocene glaciers from Mauna Kea, Hawaii, and Mt. Giluwe, Papua New Guinea. The researchers will examine glacial moraines from the Earth's tropics to gain a greater understanding of the sensitivity of the climate system to radiative forcing. Excess radiation received at low latitudes is a key driving force of the Earth's climate system. The overall goal of the research is to examine some fundamental physical elements of the response of Earth's climate to planetary radiative forcing that is significantly different from the present. Glacial moraines will be dated using cosmogenic nuclides measured on samples from surface boulders. For each field area, samples collected from moraines generally thought to represent the LGM will be dated by 3He (helium) and 36Cl (chlorine). To address questions regarding scaling and production rates of 3He at low latitudes, the project includes calibrations using Hawaiian radiocarbon dated lava flows. Climate modeling will be guided by the desire to apply improved modeling strategies to reconstruct the climate change required to sustain late Pleistocene tropical glaciation. Specifically, modeling efforts will use a physically based mass- and energy-balance glacier model that has been validated and applied to several glaciers in different topographic and climatic environments. The glacier model accounts for topographic shading, time and space varying albedo, explicit treatment of the radiation budget, and turbulent fluxes. These are important controls of glacier mass balance.The research is important because it has the potential for improving our understanding of fundamental climate processes in the tropics by providing a high-resolution chronology of glaciation in the region at the LGM, a time of important reorganization of Earth's climate regime. The research will provide a multidisciplinary educational experience in paleoclimate research for graduate students at two institutions.