"Collaborative Research: Atmospheric Dust as an Archive and Agent of Climate Change During the Late Paleozoic Icehouse"

合作研究：大气尘埃作为晚古生代气候变化的档案和因素Gerilyn Soreghan，Michael Soreghan，俄克拉荷马大学EAR-0746042 Vadimir Davydov，博伊西州立大学，EAR-0746107，Natalie Mahowald，康奈尔大学，EAR-0745961 Timothy W.Lyons，Univ.。加利福尼亚州，河滨，耳-0745602抽象大气尘埃档案和驱动气候变化。保存在海洋和大陆沉积物和冰中的尘埃揭示了最近的气候变化，尘埃还通过直接和间接影响地球表面接收的太阳能量以及通过促进初级生产力从而促进碳循环的施肥来影响气候。然而，气溶胶效应的性质和大小在气候模型中仍然是一个约束较差的变量，因此限制了这些模型的预测能力。在这项研究中，PI建议通过调查地球上一个特别多尘的地区的地质记录来评估“尘埃效应”。3亿年前的晚古生代世界非常尘土飞扬，尘埃流量在百万年和千年尺度上都有变化。这段时间也很吸引人，因为这是地球上最后一次与今天的气候相似，那里有大片极地冰盖。在这里，PI建议检验最重要的假设，即丰富的尘埃通过直接、间接和反馈效应在推动晚古生代气候变化和相关(如生物)系统的变化中发挥了重要作用。他们将调查尘埃通量、大气环流和尘埃在冰川和间冰期之间的变化，尘埃如何迫使热带气候变化，以及生物圈如何对如此高的大气灰尘做出反应。为了解决这些问题，PI瞄准了横跨热带地区的两个时间片。他们将检查尘埃分布，评估大气灰尘以及风强和风向，并使用地球化学来检查对海洋生物的影响。它们将通过化石和放射性同位素测年在不同地点进行关联。PIS将利用他们收集的数据作为气候和尘埃模拟实验的输入，评估尘埃对大气行为的直接和间接影响，并进行生物地球化学模拟，目的是评估不同营养通量对碳循环的影响。学术价值--这项研究的结果将为热带地区提供高分辨率的气候重建，并揭示尘埃对气候和生命的影响，在像今天这样的冰川世界中，尘埃在不同时间尺度上的特征是不同的尘埃通量。由于已知尘埃和相关气溶胶在气候系统中的作用的重要性，但仍然存在不确定性，我们的数据将具有预测性价值，有助于扩大我们对地球系统跨地质时间行为的理解，并将为改进气候建模提供重要的约束条件。更广泛的影响--这个项目将包括大量的学生参与(研究生和本科生)，地质学家、地球化学家和气候模型师的跨学科培训，包括实地和实验室。本科生(地质学和教育学专业)和少数民族中学生将通过辅导计划参加。将使用新开发的可通过网络访问的工具对数据进行存档和共享。最后，我们将使用这项研究的结果来指导与俄克拉何马州自然历史博物馆合作开展的关于古生代沙尘暴的巡回展览，并将结果纳入博物馆(由合作PI教授)的外展课程中。

COLLABORATIVE RESEARCH: Atmospheric Dust as an Archive and Agent of Climate Change During the Late Paleozoic Icehouse Gerilyn Soreghan, Michael Soreghan, University of Oklahoma Ear-0746042 Vadimir Davydov, Boise State University, EAR-0746107 Natalie Mahowald, Cornell University, EAR-0745961 Timothy W. Lyons, Univ. California, Riverside, EAR-0745602 Abstract Atmospheric dust archives and drives climate change. Dust preserved in marine and continental sediments and ice has shed light on recent climate change, and dust also impacts climate via direct and indirect effects on the amount of solar energy received at Earth's surface, and by fertilization that stimulates primary productivity and thus the carbon cycle. However, the character and magnitude of the aerosol effect remains a poorly constrained variable in climate models, thus limiting the predictive capability of these models. In this research, PIs propose to assess the 'dust effect' by investigating the geologic record of a particularly dusty interval on Earth. The late Paleozoic world, 300 million years ago, was remarkably dusty, with dust flux varying on both million-year and millennial scales. This time period is also attractive as the last time that Earth's climate was analogous to today's, with large polar ice sheets. Here, PIs propose to test the overarching hypothesis that the abundant dust played a significant role in driving changes in late Paleozoic climate and linked (e.g. biotic) systems, through direct, indirect, and feedback effects. They will investigate how dust flux, atmospheric circulation, and dust transport varied between glacials and interglacials, how dust forced changes in tropical climate, and how the biosphere responded to such high atmospheric dustiness. To address these questions, PIs are targeting two time slices in localities spanning the girth of the tropics. They will examine dust distribution, assess atmospheric dustiness and wind strength and direction, and use geochemistry to examine effects on marine life. They will correlate among localities using fossils and radioisotopic dating. PIs will use the data they collect as input for climate- and dust-modeling experiments, to assess the direct and indirect effects of dust on atmospheric behavior and undertake biogeochemical modeling aimed at assessing the impact of variable nutrient fluxes on cycling of carbon. Intellectual Merit-- Results of this research will provide a high-resolution reconstruction of climate for the tropics and reveal the effects of dust on climate and life in a world characterized by variable dust flux on various timescales, within a 'glacial' world like today's. Owing to the known importance but remaining uncertainty of the roles of dust and associated aerosols in the climate system, our data will have predictive utility in expanding our understanding of Earth-system behavior across geologic time, and will provide important constraints useful for improving climate modeling. Broader Impacts--This project will involve heavy student participation (graduate and undergraduate levels), cross-disciplinary training among geologists, geochemists, and climate modelers, both in the field and laboratory. Undergraduates (geology and education majors) and minority middle-schoolers will take part through mentoring programs. Data will be archived and shared using newly developed web-accessible tools. Finally, we will use results of this research to guide the development of a traveling exhibit on the 'Paleozoic Dust Bowl' in conjunction with the Oklahoma Museum of Natural History and incorporate results in an outreach course taught (by co-PIs) at the Museum.