Collaborative Research: A Synthesis of the Last 2000 Years of Climatic Variability from Arctic Lakes

合作研究：北极湖泊过去 2000 年气候变化的综合

• 批准号: 0450938
• 负责人: Jonathan Overpeck
• 金额: $ 11.1万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0450938&HistoricalAwards=false
• 关键词: Collaborative; Research; Synthesis; Last; 2000

This project contributes to understanding the Arctic system by placing 20th century climatic change into a longer-term context of inter-decadal climatic variability spanning the last 2000 yr. The centerpiece of the project is a synthesis of standardized, high-resolution proxy climate records from lakes across the North American Arctic that will advance our understanding of the role of the Arctic within the Earth system.Recent results have demonstrated that proxy climate records from the Arctic preserve a signature of summer temperature that is related to both global mean warming and the Arctic Oscillation. This conclusion was based on a synthesis limited to just the last 600 yr. Available records that extend beyond the Little Ice Age to previous warm intervals are currently too few to capture modes of variability with adequate certainty. The longer-period evolution of these modes is identifiable in decadally resolved proxy records, and should be preserved in longer records of annual to multi-decadal resolution.This synthesis of annual to inter-decadal climatic variability will extend through the key warm interval of Medieval time. The certainty of the climate reconstruction will be significantly improved by nearly tripling the number of high-resolution, 2000-yr-long, proxy climate records currently available in the Arctic. The project facilitates integration of results by standardizing the methodologies and by holding workshops for vested collaborators and their students. This tightly focused synthetic study of the Arctic system will be integrated directly into a climate-modeling effort to explore the role of volcanism and solar irradiance fluctuations versus internal adjustments of the climate system and its inherent modes of variability to explain observed patterns in the proxy climate data.Across the Arctic, lacustrine archives contain the most accessible and widely distributed proxy records for the past 2000 yr. This work focuses on 30 of the PIs' highest-priority, most-promising lakes, nearly all of which have been cored previously. The network of sites includes two regional foci (Alaska and the NW North Atlantic) that generally encompass the nodes of the surface temperature expression for the Arctic Oscillation, thereby facilitating the reconstruction of this mode of variability. Half of the lakes contain laminated sediment with potential for annually resolved records; others have high sedimentation rates for sample resolution of 5 to 30 yr. The proxy data from most lakes can be compared with nearby tree-ring records or instrumental data, or can be applied to transfer functions to yield quantitative estimates of temperature or other climatic variables. Analyses at low-resolution have already begun on most of the cores as part of on-going research. Preliminary data from these lakes indicate their high potential for climate reconstructions.

该项目通过将20世纪的气候变化置于跨越最后2000年的少年气候变异性的长期背景下，从而有助于理解北极系统。该项目的核心是综合北美北极湖中湖泊的标准化高分辨率代理气候记录，这将促进我们对北极在地球系统中的作用的理解。结果表明，从北极保存夏季温度的代理气候记录与全球平均温暖的夏季温度相关。该结论基于仅限于最后600年的合成。超出冰河时代的延伸到以前的温暖间隔的可用记录目前太少，无法以足够的确定性来捕获变异性模式。这些模式的长期演变可以在十年后解决的代理记录中识别，并应保留在较长的年度至多年分辨率的较长记录中。这综合了年度至十年间气候变化的综合，将延伸到中世纪的关键温暖间隔。通过几乎三倍的高分辨率，2000年，长达2000年的代理气候记录，气候重建的确定性将得到显着提高。该项目通过标准化方法和为既得合作者及其学生举办研讨会来促进结果的整合。 This tightly focused synthetic study of the Arctic system will be integrated directly into a climate-modeling effort to explore the role of volcanism and solar irradiance fluctuations versus internal adjustments of the climate system and its inherent modes of variability to explain observed patterns in the proxy climate data.Across the Arctic, lacustrine archives contain the most accessible and widely distributed proxy records for the past 2000 yr.这项工作重点介绍了30个PI的最高优先级，最有经验的湖泊，几乎所有这些湖泊先前已经掌管。地点网络包括两个区域灶（阿拉斯加和西北大西洋），通常包含北极振荡的表面温度表达节点，从而促进了这种可变性方式的重建。一半的湖泊含有层压沉积物，每年都有解决记录的潜力；其他人的沉积率很高，可分辨率为5至30年。可以将来自大多数湖泊的代理数据与附近的树环记录或工具数据进行比较，也可以应用于传输功能以产生温度或其他气候变量的定量估计。作为正在进行的研究的一部分，低分辨率的分析已经开始对大多数核心进行。这些湖泊的初步数据表明它们的气候重建潜力很高。