Collaborative Research: Quantitative Estimates of Holocene Warmth and Climate Variability Derived from Icelandic Lake Sediments

合作研究：冰岛湖沉积物对全新世温暖和气候变化的定量估计

• 批准号: 0317766
• 负责人: Matthew Wooller
• 金额: $ 14.81万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0317766&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantitative; Estimates; Holocene

This award will evaluate the role of polar amplification, and derive quantitative estimates of warmth through the Holocene of Iceland. Iceland occupies a strategic position to monitor North Atlantic climate, as it is situated at the boundary between major oceanic and atmospheric circulation systems. Consequently, Iceland records the status of much of the northern North Atlantic region. This award will address Arctic warmth by reconstructing the status of Iceland's ice caps from changes in the physical properties of sediment accumulating in glacier-dominated lakes. Ice-cap modeling will provide quantitative estimates of past summer warmth consistent with reconstructions of the ice cap derived from the lake sediment study. The oxygen isotopic ratio (delta18O) of precipitation will be determined from the delta18O of chironomid (midge) head capsules, a common constituent of arctic lake sediment. The delta18O of Arctic precipitation is highly correlated with mean annual air temperature, providing quantitative temperature reconstructions. Chironomid delta18O provides quantitative estimates of past air temperatures from Arctic lakes, and circumvents persistent problems with low pollen productivity at high latitudes and with plant immigration delays. Changes in chironomid assemblages in the same sediment cores, tied to an Icelandic training set, will provide an independent estimate of summer temperature.Three U.S. PhD students will be involved in this project. In addition, two Icelandic graduate students and one postdoc will be involved in a companion study with Icelandic collaborators. Film footage of the Hvitarvatn coring may be used in a proposed public television program on climate change. Thermohaline circulation is the greatest non-linearity in the climate system. By providing quantitative data on Holocene warmth and status of ice caps, this work will provide a key benchmark for General Circulation Models, especially those attempting to simulate thermohaline circulation. Results will be of great interest to Icelanders, who depend on their ice caps for hydroelectric power and as major tourist attractions. If Iceland's ice caps are at risk from projected global warming, this will have substantial economic impacts. This research will help constrain those risks.

该奖项将评估极地放大的作用，并得出冰岛全新世气温的定量估计。冰岛位于主要海洋和大气环流系统的交界处，在监测北大西洋气候方面具有战略地位。因此，冰岛记录了北大西洋北部地区的大部分地区的状况。该奖项将通过冰川为主的湖泊中积累的沉积物物理性质的变化来重建冰岛冰盖的状况，以解决北极的温暖问题。冰盖模拟将提供对过去夏季暖度的定量估计，这与从湖泊沉积物研究得出的冰盖重建一致。降水的氧同位素比(Delta18O)将从摇蚊(侏儒)头胶囊的delta18O确定，摇蚊头囊是北极湖沉积物的常见成分。北极降水的DELTA18O与年平均气温高度相关，提供了定量的温度重建。摇蚊delta18O提供了对北极湖泊过去气温的定量估计，并绕过了高纬度花粉生产力低和植物迁徙延迟的持续问题。同一沉积物岩心中摇蚊组合的变化，与冰岛的训练集相联系，将提供对夏季温度的独立估计。三名美国博士生将参与这一项目。此外，两名冰岛研究生和一名博士后将与冰岛合作者一起进行同伴研究。Hvitarvatn岩芯的电影片段可能会被用于拟议中的一个关于气候变化的公共电视节目。温盐环流是气候系统中最大的非线性。通过提供有关全新世温度和冰盖状况的定量数据，这项工作将为大气环流模型提供一个关键基准，特别是那些试图模拟温盐环流的模型。这一结果将引起冰岛人的极大兴趣，他们依赖冰盖提供水电，并作为主要的旅游景点。如果冰岛的冰盖面临预计的全球变暖的风险，这将产生重大的经济影响。这项研究将有助于限制这些风险。