Collaborative Research: Sub-Millennial Hydroclimatic Variability in the Northeastern United States during the Holocene

合作研究：全新世美国东北部次千年水文气候变化

• 批准号: 0602408
• 负责人: Bryan Shuman
• 金额: $ 13.55万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2010-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0602408&HistoricalAwards=false
• 关键词: Collaborative; Research; Sub; Millennial; Hydroclimatic

Hydrologic variability poses significant challenges to society. However, the potential for hydrologic change remains poorly understood. Sedimentary patterns within small lake basins record past changes in water levels and can be used to track shifts in moisture availability over time. This study assesses hydrologic variability at the scale of millennia and centuries over the past 11,000 years in Massachusetts, where existing lake sedimentary data appear to indicate significant changes in the frequency of past droughts. The creation, analysis, and synthesis of new, well-resolved sedimentary data, in combination with detailed fossil pollen data, is used to evaluate sub-millennial hydrologic variability, its controls, and its effects.Intellectual MeritPast hydroclimatic variation is poorly understood, especially in humid temperate regions. Little is known about the frequency, magnitude, and cause of variations. Stratigraphic records of lakelevel change in the northeastern U.S. can provide new insight into important regional to global climatic processes. High-resolution geophysical surveys and sediment cores of lakes in the northeastern U.S. have documented climatically meaningful patterns in the sedimentary record - and indicate possible changes in high-frequency hydrologic variability. Existing data appear to indicate a series of low lake stands of millennial and sub-millennial duration between 6000 and 2000 years ago in contrast to little variability on these time scales during earlier and later portions of the Holocene. This grant studies four lakes to produce detailed lake-level histories. Similarities and differences among the histories are used to evaluate past hydroclimatic changes and to better understand the causes of the apparent high frequency variation. Temperature reconstructions also indicate warmer than modern winters in the northeastern U. S. in the mid-Holocene. Given the potential to understand the effects of future climate warming through analogy, this project evaluates possible linkages between past warmth and hydroclimatic variation. By comparing sediment and pollen data, the group also investigates biotic responses to past climatic changes.Broader ImpactsWater is a vital resource and risk of drought is a major societal concern. Questions exist about the potential for dramatic hydrologic change in humid, heavily populated regions like the eastern U.S. Expectations of future climate warming increase the need to understand the mechanisms that drive changes in water resources. This study offers important baseline data regarding the range of regional hydrologic variability and its ecological impacts. This data provides insight into water resource responses to climatic conditions like those predicted for the future. The results of this study are useful to a wide variety of stakeholders from agricultural businesses to habitat conservation groups and municipalities concerned with managing water supplies and mitigating drought risk. Resource managers and policy makers have access to the results to make informed decisions. This project also advances the development of young researchers while promoting innovative science.

水文变化给社会带来了重大挑战。然而，人们对水文变化的潜力仍知之甚少。小湖盆内的沉积模式记录了过去水位的变化，可用于跟踪水分可用性随时间的变化。这项研究评估了马萨诸塞州过去 11,000 年来数千年和几个世纪的水文变化，现有的湖泊沉积数据似乎表明过去干旱频率的显着变化。新的、分辨率良好的沉积数据的创建、分析和综合，与详细的化石花粉数据相结合，用于评估亚千禧年的水文变化、其控制及其影响。智力优点过去的水文气候变化人们知之甚少，特别是在温带湿润地区。对于变化的频率、幅度和原因知之甚少。美国东北部湖面变化的地层记录可以为重要的区域到全球气候过程提供新的见解。美国东北部湖泊的高分辨率地球物理调查和沉积岩芯记录了沉积记录中具有气候意义的模式，并表明高频水文变率可能发生的变化。现有数据似乎表明，在 6000 至 2000 年前，存在一系列持续千年和亚千年的低湖水位，而在全新世早期和晚期，这些时间尺度的变化很小。这笔赠款研究了四个湖泊，以产生详细的湖泊水位历史。历史之间的相似点和差异用于评估过去的水文气候变化，并更好地理解明显高频变化的原因。气温重建还表明，全新世中期美国东北部的冬季比现代冬季温暖。鉴于通过类比了解未来气候变暖影响的潜力，该项目评估了过去的温暖与水文气候变化之间可能的联系。通过比较沉积物和花粉数据，该小组还研究了生物对过去气候变化的反应。更广泛的影响水是一种重要资源，干旱风险是一个主要的社会问题。对于美国东部等潮湿、人口稠密地区是否可能发生剧烈水文变化存在疑问。对未来气候变暖的预期增加了了解驱动水资源变化的机制的必要性。这项研究提供了有关区域水文变异范围及其生态影响的重要基线数据。这些数据可以深入了解水资源对气候条件（如未来预测的气候条件）的反应。这项研究的结果对从农业企业到栖息地保护团体和关心管理供水和减轻干旱风险的市政当局等各种利益相关者都有用。资源管理者和政策制定者可以访问结果以做出明智的决策。该项目还促进了年轻研究人员的发展，同时促进创新科学。