Collaborative research: Exploring the role of oceanic and atmospheric forcing on Arctic marine climate from newly developed annual shell based records in coastal Norway

合作研究：从挪威沿海新开发的年度贝壳记录中探索海洋和大气强迫对北极海洋气候的作用

• 批准号: 1417766
• 负责人: Alan Wanamaker
• 金额: $ 47.27万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1417766&HistoricalAwards=false
• 关键词: Collaborative; research; Exploring; role; oceanic

Oceanographers and paleoclimatologists use various proxies to study the past history of ocean temperature and salinity. Many of these are recorded in the marine sediments, but sedimentation rates are so small that the time series that can be estimated from them only resolve changes that occur on decadal time scales or longer. When clams and other bivalves grow, they incorporate, in their shells, geochemical signatures from the water in which they live. They also lay down growth rings, like tree rings, in their shells. By studying the chemistry of adjacent rings in long-lived clam shells the principal investigators (PIs) of this project expect to be able to reconstruct the annual temperature and salinity variations of near surface waters in a region offshore of northern Norway. They will focus their efforts on the Medieval Warm Period (1000 AD to 1200 AD), the Little Ice Age (1200 AD to 1850 AD), and the modern era (1850 AD until the present). The resultant histories of temperature and salinity variation will be useful for understanding how the ocean conditions changed during these known periods of climate variation and for validating or constraining climate models.The PIs? immediate goal is to reconstruct annual hydrographic variability during key climate intervals within the last millennium along the strategically located Arctic islands of Ingoy and Rolvsoy. They will hindcast changes in annual sea surface temperature (SST) and sea surface salinity (SSS). They will also establish the baseline variability in the marine radiocarbon reservoir effect. The modern near-surface oceanography along the islands is influenced by the physical properties of the Norwegian Coastal Current, while the relatively deep hydrographic conditions predominately depend on Atlantic inflow. Pilot data from the study site demonstrate a strong link between shell-based records and regional SST/SSS conditions. Hence, Ingoy and Rolvsoy seem situated in an ideal location to study marine climate change during the late Holocene. Hypotheses and objectives have been developed to test the relative influence of dominant climate modes on the regional oceanography near northern Norway during the last millennium.Objective 1: Develop near-surface annual shell-based records (master shell chronology and isotopes) to reconstruct regional hydrographic variability (SST and SSS) along the northernmost coast of Norway during intervals of the Medieval Climate Anomaly, the Little Ice Age, and for Modern Climate.Objective 2: Develop relatively deep-water (200 m) annual shell-based records (master shell chronology and isotopes) for the last 100 years to characterize the role of the North Atlantic Current on hydrography at the site.Objective 3: Establish a decadal record of the surface marine radiocarbon reservoir effect since AD 1600 to estimate changes in source water contributions at Ingoy.Objective 4: Estimate the relative influence of the winter North Atlantic Oscillation, the surface Atlantic Meridional Overturning Circulation, and the Atlantic Multidecadal Oscillation on regional hydrography (at Ingoy) and shell-based records.An international partnership for studying Arctic marine climate change will be developed with colleagues from the Akvaplan-niva (Norway), Iowa State University (ISU) and Bates College (Maine). Outreach, public engagement, and dissemination of the results will be accomplished through engagement of two K-12 teachers in the field work, through classroom interactions with K-12 students, through a K-12 teacher workshop, through citizen-based science (via interactions with native Norwegians at Ingoy), and via a photo-journalist who will join the PIs for one field season. At least one female PhD student and approximately five undergraduate students will be supported by and involved with the project. The PIs will use data and ideas developed in this project for several courses at ISU and Bates College relating to climate change, paleoclimate and oceanography. PI Wanamaker will facilitate a public lecture series on climate change at the Ames Public library and continue to act as co-chair of Edwards Elementary Science Night, which has impacted 1,000 students and community members since 2012.

海洋学家和古气候学家使用各种代用指标来研究海洋温度和盐度的历史。 其中许多都记录在海洋沉积物中，但沉积速率非常小，因此可以从中估计的时间序列只能解决十年或更长时间尺度上发生的变化。 当蛤和其他双壳类动物生长时，它们的壳中会包含它们所生活的水的地球化学特征。 它们还在壳里留下生长环，就像树木的年轮一样。 通过研究长寿蛤蜊壳中相邻环的化学性质，该项目的主要研究人员（PI）预计能够重建挪威北方近海区域近地表沃茨的年度温度和盐度变化。 他们将集中精力在中世纪温暖时期（公元1000年至公元1200年），小冰河时期（公元1200年至公元1850年）和现代时期（公元1850年至今）。 由此产生的温度和盐度变化的历史将有助于了解如何在这些已知的气候变化时期的海洋条件变化，并验证或约束气候模型。近期目标是重建上个千年沿着北极战略性岛屿Ingoy和Rolvsoy关键气候间隔期间的年度水文变化。他们将对年海表温度（SST）和海表盐度（SSS）的变化进行后报。他们还将确定海洋放射性碳库效应的基线变异性。现代近表层海洋学沿着的岛屿是由挪威沿岸流的物理特性的影响，而相对较深的水文条件主要取决于大西洋流入。研究现场的试验数据表明，基于外壳的记录与区域SST/SSS条件之间存在密切联系。因此，Ingoy和Rolvsoy似乎位于研究晚全新世海洋气候变化的理想位置。已经提出了一些假设和目标，以检验上个千年期间主导气候模式对挪威北方附近区域海洋学的相对影响。开发近地表年度贝壳记录（主壳年代学和同位素）重建区域水文变化（SST和SSS）沿着挪威最北海岸在中世纪气候异常、小冰期和现代气候期间的变化。开发相对深水（200米）的年度贝壳记录（主贝壳年代学和同位素），以确定北大西洋洋流对该地点水文地理的作用。建立自公元1600年以来海洋表层放射性碳库效应的十年记录，以估计因戈伊水源贡献的变化。目标4：估计冬季北大西洋涛动、地面大西洋经向翻转环流和大西洋年代际涛动对区域水文地理学（在因戈伊）和贝壳记录的相对影响。将与Akvaplan-niva（挪威）、爱荷华州州立大学（ISU）和贝茨学院（缅因州）的同事建立研究北极海洋气候变化的国际伙伴关系。推广，公众参与和传播的结果将通过两个K-12教师在实地工作的参与，通过课堂互动与K-12学生，通过K-12教师研讨会，通过以公民为基础的科学（通过与挪威本地人在Ingoy的互动），并通过摄影记者谁将加入一个领域的季节PI。至少有一名女博士生和大约五名本科生将得到该项目的支持和参与。研究所将利用该项目中开发的数据和想法，在国际空间大学和贝茨学院开设与气候变化、古气候和海洋学有关的几门课程。PI Wanamaker将在艾姆斯公共图书馆举办一系列关于气候变化的公开讲座，并继续担任爱德华兹小学科学之夜的联合主席，该活动自2012年以来已影响了1,000名学生和社区成员。