OPP-PRF: Assessing the relationship among fire, temperature, and precipitation in the Arctic during the Pleistocene

OPP-PRF：评估更新世期间北极火灾、温度和降水之间的关系

• 批准号: 2138893
• 负责人: Emily Tibbett
• 金额: $ 28.56万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2138893&HistoricalAwards=false
• 关键词: OPP; PRF; Assessing; relationship; among

Rising temperatures associated with increasing atmospheric carbon dioxide (CO2) concentrations are causing more fire events globally, including in the Arctic. Arctic fire events have regional impacts including changing the plant community to those that are more flammable. In addition, the burning of previously frozen Arctic soils can release stored carbon, adding more CO2 to the atmosphere. The intensity and number of wildfires in a region are controlled mainly by temperature and precipitation. Climate models can project future temperature well but regional precipitation data are limited which hampers the ability to accurately project Arctic wildfires. This study will compare wildfire frequency to temperature and precipitation during times in the past that were not influenced by human activity. The results can be used to improve regional Arctic climate models of precipitation impact on fire frequency. Results of this study will be communicated to policymakers to assist with decision making in response to future warming. The project will generate educational materials and hands-on science projects related to climate change and fire in the Arctic for outreach to primary school students around the country through virtual classrooms. The project will engage undergraduates through lab work, a conference presentation, and a workshop for the Eureka! Summer Science Camp at the University of Massachusetts which engages girls ages 12-18 to explore STEM fields. Fire disturbances are predicted to increase in the Arctic with rising temperatures while precipitation also impacts fire frequency and intensity. Future projections show increases in temperature, precipitation, and fire events. However, climate models are limited in their ability to reconstruct precipitation, which inhibits estimates of fire frequency. In addition, it is unclear if precipitation is the primary driver of fire frequency or if it works in tandem with rising temperatures. Previous assessments of past Arctic fires have produced contrasting results with both wetter and more arid conditions being associated with an increase in fire. To address this, more precipitation records that exclude the impact of human-induced fires are needed to constrain potential feedbacks. This research will investigate variability in Arctic climate through reconstructing precipitation, temperature, and fire throughout the Pleistocene using organic geochemical techniques. Ocean Drilling Program Site 647, located near southern Greenland, will be studied as this Site spans known interglacials such as Marine Isotope Stage (MIS) 11 and super interglacial MIS 31-33. Sea surface temperatures (SST) generated from three different organic geochemical techniques will be compared to concentrations of compounds produced by burning biomass, such as polycyclic aromatic hydrocarbons (PAHs) and levoglucosan. These data will allow examination of time periods of increasing wildfires in connection with the temperature history. The SST and fire biomarker concentration will be compared to hydrogen isotopes (δ2H) of plant leaf waxes from the same core, which provides additional information on moisture transport pathways in the Arctic. The study will evaluate if higher temperatures during interglacials result in more poleward moisture transport, which is reflected in more enriched δ2H due to changes in moisture source as increasing temperatures leads to wetter conditions in the Arctic. Overall, the use of multiple proxies will generate new records spanning both glacial and interglacial periods across the Pleistocene to assess variability in the relationships between temperature, precipitation, moisture source, and fire in the Arctic.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.

与大气二氧化碳浓度增加相关的气温上升正在全球范围内造成更多的火灾事件，包括在北极地区。 北极火灾事件具有区域性影响，包括将植物群落改变为更易燃的植物群落。此外，燃烧之前冻结的北极土壤可以释放储存的碳，向大气中增加更多的二氧化碳。一个地区野火的强度和数量主要受温度和降水量的控制。气候模型可以很好地预测未来的温度，但区域降水数据有限，这阻碍了准确预测北极野火的能力。这项研究将比较野火频率与过去不受人类活动影响的温度和降水量。 研究结果可用于改进降水对火灾频率影响的北极区域气候模型。这项研究的结果将传达给政策制定者，以帮助他们做出应对未来变暖的决策。该项目将制作与北极气候变化和火灾有关的教材和实践科学项目，通过虚拟教室向全国各地的小学生推广。 该项目将通过实验室工作，会议演示和尤里卡研讨会吸引本科生！马萨诸塞州大学的暑期科学营，吸引12-18岁的女孩探索STEM领域。随着气温的上升，北极地区的火灾干扰预计会增加，而降水也会影响火灾的频率和强度。未来的预测显示温度、降水和火灾事件会增加。然而，气候模型重建降水的能力有限，这抑制了对火灾频率的估计。此外，目前还不清楚降水是否是火灾频率的主要驱动因素，或者它是否与气温上升同步起作用。以前对过去北极火灾的评估产生了对比鲜明的结果，潮湿和干旱的条件都与火灾的增加有关。 为了解决这个问题，需要更多的降水记录，排除人为火灾的影响，以限制潜在的反馈。这项研究将通过使用有机地球化学技术重建整个更新世的降水，温度和火灾来调查北极气候的变化。将对位于格陵兰岛南部附近的大洋钻探计划647号地点进行研究，因为该地点跨越海洋同位素阶段（MIS）11和超级间冰期MIS 31-33等已知间冰期。海洋表面温度（SST）产生的三种不同的有机地球化学技术将比较燃烧生物质，如多环芳烃（PAH）和左旋葡聚糖产生的化合物的浓度。这些数据将允许检查与温度历史有关的野火增加的时间段。SST和火灾生物标志物的浓度将与来自同一岩芯的植物叶蜡的氢同位素（δ 2 H）进行比较，这提供了关于北极水分输送途径的更多信息。该研究将评估间冰期期间的高温是否会导致更多的水分向极地输送，这反映在随着气温升高导致北极地区更加潮湿的条件下，由于水分来源的变化而导致δ 2 H更加富集。 总体而言，使用多个代理将产生新的记录跨越冰期和间冰期整个更新世，以评估温度，降水，水分来源之间的关系的变化，并在北极火灾。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。