Collaborative Research: A North Pacific ice core record of summer climate and wildfire history during the last 1500 years

该项目打算利用德纳里山冰芯档案来开发自距今约2500年以来最全面的北太平洋火灾和夏季气候代理记录。野火是北太平洋夏季气候的关键组成部分，预计随着夏季持续变暖，野火将增加。因此，迫切需要将夏季气候和野火的古记录结合起来进行研究，特别是在北太平洋地区，那里的火灾复发率和十年至百年尺度的气候波动发生的时间比直接观测所覆盖的时间更长。拟议研究的目标是提高我们对夏季气候和野火活动之间关系的理解，特别是关注中世纪气候异常（MCA），当时区域温度可能与20世纪一样温暖。最近的进展现在允许测量冰芯中新的与火灾有关的（热原）化合物，从而能够建立一个可靠的火灾记录，能够与区域古气候重建进行严格的比较。通过该项目开发的夏季大气环流记录将是区域独特的，并填补了北太平洋古气候记录套件的关键空白。冰芯火灾记录将具有同步日期的温度、降水和环流时间序列。我们对这些冰芯记录以及其他区域性古代用记录的独特汇编，将是将这些数据集结合成北太平洋地区古火记录区域性汇编的第一次努力。该汇编将有助于研究中世纪气候异常（MCA）条件下的火灾活动，这些条件与当前社会相关时间尺度（几十年）的气候变化具有可比的量级。我们将分析Denali冰芯档案中的黑碳，黑碳来自生物质和化石燃料燃烧，有机芳香酸（如香草酸）和单糖酸酐（如左旋葡聚糖）仅来自生物质燃烧。Denali冰芯年代学已经开发出来，并且存档冰已经到手，确保我们的研究计划可以完成。火灾记录的合成和校准将结合仪器火灾数据库、网格化烧伤面积数据和HYSPLIT在仪器时代的反轨迹分析，以测试随时间变化的火灾气候关系的敏感性。利用这一记录，我们将解决以下研究问题：(1)在过去1500年中，北太平洋夏季大气环流模式是如何变化的？(2)北太平洋火情特征如何自然响应中世纪气候异常（MCA）的温暖夏季条件？(3)北太平洋火情与气候的关系是否一致？我们更广泛影响的一个焦点是支持两位年轻的调查人员，他们分别在北太平洋冰芯和古火建模方面具有专门知识。该项目还将资助一名博士生和几名本科生。我们将继续与德纳里国家公园的长期合作，在阿拉斯加塔尔基特纳的公园游客中心永久展示我们的主要气候和火灾相关发现。我们正在与科罗拉多州立大学的自然科学教育和推广中心合作，开发专注于德纳里冰芯记录的STEM工具包，分发给阿拉斯加和缅因州服务不足的K-12学生。这些工具包的原型已经开发出来，并在学生中进行了测试，我们建议大大扩展这个项目，增加其影响。其他活动包括作为达特茅斯女性参与科学项目（WISP）倡议的一部分，一年级女性研究人员参与该项目，并通过参与nsf支持的冰学院，在那里，来自历史上黑人大学和少数民族服务机构的教师学习冰芯和气候变化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project intends to use the Mount Denali ice core archive to develop the most comprehensive suite of North Pacific fire and summer climate proxy records since about 2500 years before present. Wildfire is a key component of summer climate in the North Pacific where wildfires are projected to increase with continued summer warming. Studies that combine paleorecords of summer climate and wildfire are therefore critically needed, especially in the North Pacific region where fire recurrence rate and decadal-to-centennial scale climate fluctuations occur over longer time periods than are covered by direct observations. The goal of the proposed research is to improve our understanding of relationships between summertime climate and wildfire activity, focusing especially on the Medieval Climate Anomaly (MCA), when regional temperatures were perhaps as warm as the 20th century. Recent advances now permit the measurement of new fire-related (pyrogenic) compounds in ice cores, enabling the development of a robust fire record capable of rigorous comparison with regional paleoclimate reconstructions. The records of summer atmospheric circulation developed through this project will be regionally unique and fill a critical gap in the suite of North Pacific paleoclimate records. The ice core fire records will have synchronously dated temperature, precipitation and circulation time series. Our unique compilation of these ice core records, as well as other regional paleoproxy records will be the first effort at combining these datasets into a regional compilation of paleofire records in the North Pacific region. This compilation will facilitate the examination of fire activity during Medieval Climate Anomaly (MCA) conditions that are of comparable magnitude to present climate changes over socially relevant timescales (decades). We will analyze the archive Denali ice core for black carbon, which is derived from both biomass and fossil fuel combustion, and organic aromatic acids (e.g. vanillic acid) and monosaccharide anhydride (e.g. levoglucosan) which are produced solely from biomass burning. The Denali ice core chronology is already developed, and the archive ice is in hand, ensuring that our research plan can be accomplished. Fire record synthesis and calibration will incorporate instrumental fire databases, gridded burn area data, and HYSPLIT back-trajectory analyses over the instrumental era in order to test the sensitivity of fireclimate relationships over time. With this record we will address the following research questions: (1) How have North Pacific summer atmospheric circulation patterns varied over the last 1500 years? (2) How did North Pacific fire regime characteristics naturally respond to the warm summer conditions of the Medieval Climate Anomaly (MCA)? (3) Are there consistent relationships between North Pacific fire regime and climate?A focal point of our broader impacts is support for two young investigators who have specialized expertise in North Pacific ice cores and paleofire modeling, respectively. This project will also support one PhD student and several undergraduate students. We will continue our longstanding collaboration with Denali National Park to present and permanently display our major climate- and fire-related findings at the park visitor center in Talkeetna, Alaska. We are partnering with the Natural Sciences Education and Outreach Center at Colorado State University to develop STEM kits focused on the Denali ice core record for distribution to under-served K-12 students in Alaska and Maine. Prototypes of these kits have already been developed and tested with students, and we propose to significantly expand this program and increase its impact. Other activities include the participation of first-year women researchers in this project as part of the Dartmouth Women In Science Project (WISP) initiative, and through participation in the NSF-supported School of Ice, where faculty from historically black colleges and minority-serving institutions learn about ice cores and climate change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.