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: 0455089
• 负责人: David Porinchu
• 金额: --
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 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 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0455089&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.

该项目将世纪的气候变化置于跨越过去2000年的年代际气候变率的长期背景下，有助于理解北极系统。该项目的核心是综合北美北极地区湖泊的标准化、高分辨率代用气候记录，这将促进我们对北极在地球系统中作用的理解。最近的结果表明，北极的代用气候记录保存了夏季温度的特征，这与全球平均变暖和北极涛动都有关。这一结论是基于仅限于过去600年的综合。目前，从小冰期到以前温暖时期的现有记录太少，无法充分确定地捕捉变化模式。这些模式的长期演变可以在年代际分辨率的代用记录中识别，并且应该在年度到多年代分辨率的长期记录中保存下来。气候重建的确定性将大大提高，通过增加近三倍的高分辨率，2000年之久，代用气候记录目前在北极。该项目通过使方法标准化和为既定合作者及其学生举办讲习班，促进成果的整合。北极系统的这一集中的综合研究将被直接整合到气候模拟工作中，以探索火山活动和太阳辐照度波动对气候系统内部调整的作用及其内在的变化模式，以解释在代用气候数据中观察到的模式。在整个北极，湖泊档案包含过去2000年最容易获得和广泛分布的代用记录。这项工作的重点是PI的30个最高优先级，最有前途的湖泊，几乎所有这些湖泊都已被取芯以前。该网络的网站包括两个区域焦点（阿拉斯加和西北北大西洋），一般包括北极涛动的表面温度表达式的节点，从而促进重建这种模式的变化。一半的湖泊含有层状沉积物，每年解决记录的潜力，其他人有高沉积速率的样品分辨率为5至30年。来自大多数湖泊的代用数据可以与附近的树木年轮记录或仪器数据进行比较，或者可以应用于传递函数，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，已经开始对大多数岩心进行低分辨率分析。这些湖泊的初步数据表明，它们具有很高的气候重建潜力。