COLLABORATIVE RESEARCH: Atmospheric Dust as an Archive and Agent of Climate ChangeDuring the Late Paleozoic Icehouse

合作研究：晚古生代冰室期间大气尘埃作为气候变化的档案和媒介

• 批准号: 0745602
• 负责人: Timothy Lyons
• 金额: $ 20万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-15 至 2013-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0745602&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Atmospheric; Dust; Archive

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.

合作研究：晚古生代冰室期间大气尘埃作为气候变化的档案和媒介 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西里昂大学加利福尼亚州河滨市，EAR-0745602 摘要 大气尘埃档案并驱动气候变化。海洋和大陆沉积物和冰中保存的灰尘揭示了最近的气候变化，灰尘还通过直接和间接影响地球表面接收到的太阳能量以及通过刺激初级生产力和碳循环的施肥来影响气候。 。然而，气溶胶效应的特征和程度仍然是气候模型中约束较差的变量，从而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灰尘特别多的区间的地质记录来评估“灰尘效应”。三亿年前的晚古生代世界充满了尘埃，尘埃通量在百万年和千年尺度上变化。这个时期也很有吸引力，因为地球气候最后一次与今天的气候相似，有大片的极地冰盖。在这里，PI 提议检验一个总体假设，即丰富的尘埃通过直接、间接和反馈效应，在驱动晚古生代气候和相关（例如生物）系统的变化方面发挥了重要作用。他们将研究冰川期和间冰期之间的尘埃通量、大气环流和尘埃输送如何变化，尘埃如何迫使热带气候发生变化，以及生物圈如何对如此高的大气尘埃量做出反应。为了解决这些问题，PI 将目标定为跨越热带地区的两个时间片。他们将检查灰尘分布，评估大气灰尘含量以及风力和风向，并利用地球化学研究对海洋生物的影响。他们将使用化石和放射性同位素测年法来关联不同地点。 PI将使用他们收集的数据作为气候和灰尘建模实验的输入，以评估灰尘对大气行为的直接和间接影响，并进行生物地球化学建模，旨在评估可变养分通量对碳循环的影响。智力价值——这项研究的结果将提供热带气候的高分辨率重建，并揭示灰尘对气候和生命的影响，在一个以不同时间尺度变化灰尘通量为特征的世界中，在像今天这样的“冰川”世界中。由于灰尘和相关气溶胶在气候系统中的作用的重要性已知，但仍然存在不确定性，我们的数据将在扩大我们对跨地质时期地球系统行为的理解方面具有预测效用，并将为改进气候建模提供有用的重要约束。更广泛的影响——该项目将涉及大量学生参与（研究生和本科生），以及地质学家、地球化学家和气候建模师在现场和实验室的跨学科培训。本科生（地质和教育专业）和少数民族中学生将通过辅导项目参与其中。数据将使用新开发的网络访问工具进行存档和共享。最后，我们将利用这项研究的结果来指导与俄克拉荷马州自然历史博物馆联合举办的“古生代沙尘暴”巡回展览，并将结果纳入博物馆（由联合PI）教授的外展课程中。