Collaborative Research: Centennial-to-Millennial-Scale Climatic Fluctuations in Northeast Siberia during the Last Glacial Cycle

合作研究：末次冰期期间西伯利亚东北部百年至千年尺度的气候波动

• 批准号: 0117107
• 负责人: Glenn Berger
• 金额: $ 2.58万
• 依托单位: Nevada System of Higher Education, Desert Research Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0117107&HistoricalAwards=false
• 关键词: Collaborative; Research; Centennial; Millennial; Scale

Studies of Earth's history show that climate is capable of changing rapidly (within a few years or decades) and dramatically (from glacial to interglacial conditions). The response of the Earth's ecosystems to such global-scale changes can be spatially complex. Paleoclimatic fluctuations are evident during the last glacial cycle (~12,000 and 110,000 years ago) when temperatures were generally cooler than present and were interrupted by 24 warm events during which temperature ranged from 15-20 degrees C. Understanding the mechanisms and timing of such environmental change is particularly important for the Arctic, a region particularly sensitive to climate variability. Historically, data from the Greenland ice sheet has been the foundation for paleoclimatic reconstruction for the region. Still lacking, however, is an understanding of how northern ecosystems have responded to changes in climate.This research will address this knowledge gap by providing the first continuous, high-resolution, multi-proxy record of paleovegetational and paleoclimatic change from the Arctic for the period ~22,000 to 50,000 years ago. A sediment core from Elikchan Lake in northeast Siberia will be recovered and analyzed for pollen and diatom remains as well as sediment geochemistry with sufficient temporal control to be compared to climate trends found in ice cores. These new data will be used to define the number, magnitude, and timing of climatic fluctuations to assess the similarities and differences in the climate histories between the eastern (North Atlantic) and western (northeast Siberia) Arctic. Specifically, the research will: 1) evaluate computer simulations of past temperature in northern Asia as related to climatic and oceanic changes in the North Atlantic region; 2) explore the role of Siberia in transmitting climatic fluctuations originating in the North Atlantic to the North Pacific; and 3) examine the range of ecosystem responses to various climatic conditions and the potential importance of biofeedback to the climate system (e.g., whether changes in the distribution of boreal forests, a major methane source, can affect levels of methane in the atmosphere).

对地球历史的研究表明，气候能够迅速（在几年或几十年内）和急剧（从冰期到间冰期）变化。地球生态系统对这种全球尺度变化的反应在空间上可能是复杂的。古气候波动在最后一个冰期（~12,000至110,000年前）期间是明显的，当时气温普遍比现在低，并被24次温度范围在15-20摄氏度之间的温暖事件打断。了解这种环境变化的机制和时间对于对气候变化特别敏感的北极地区尤为重要。从历史上看，格陵兰冰盖的数据一直是该地区古气候重建的基础。然而，对北方生态系统如何应对气候变化的理解仍然缺乏。这项研究将通过提供第一个连续的、高分辨率的、多代理的记录来解决这一知识空白，记录的是22000年到50000年前北极地区的古植被和古气候变化。从西伯利亚东北部的Elikchan湖提取的沉积物岩心将被回收并分析花粉和硅藻残留物，以及沉积物地球化学，并与冰芯中发现的气候趋势进行足够的时间控制。这些新数据将用于确定气候波动的数量、幅度和时间，以评估北极东部（北大西洋）和西部（西伯利亚东北部）气候历史的异同。具体而言，该研究将：1)评估北亚过去温度的计算机模拟与北大西洋地区气候和海洋变化的关系；2)探索西伯利亚在将源自北大西洋的气候波动传递到北太平洋中的作用；3)研究生态系统对各种气候条件的响应范围以及生物反馈对气候系统的潜在重要性（例如，作为主要甲烷来源的北方森林分布的变化是否会影响大气中甲烷的水平）。