The Anatomy of Last Glacial Maximum (LGM) Climate Change in the Southern Hemisphere Mid-Latitudes: Paleoecological Temperature Reconstructions from Terrestrial Archives

南半球中纬度地区末次盛冰期（LGM）气候变化的剖析：从陆地档案中重建古生态温度

• 批准号: 0902386
• 负责人: Marcus Vandergoes
• 金额: $ 33.94万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0902386&HistoricalAwards=false
• 关键词: Anatomy; Last; Glacial; Maximum; LGM

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The objective of this research is to test if leading hypotheses about drivers of global ice ages explain climate change in the Southern Hemisphere mid-latitudes. The research establishes the timing, magnitude, and structure of southern mid-latitude Last Glacial Maximum climate from two sites bordering the Southern Alps, New Zealand, by reconstructing temperature changes from continuous, isotopically dated, paleo-chironomid and pollen re-cords.Hypotheses about what drives ice age climate change remain clouded with ambiguities because the timing and magnitude of maximum ice age cooling (Last Glacial Maximum, LGM) does not appear to match between the Northern and Southern Hemispheres. Northern solar insolation is held responsible for driving Southern Hemisphere climate changes even though the intensity and duration of southern insolation is out of phase with that of the north. Apparent mismatches in the timing of LGM climate changes between the hemispheres cannot be adequately explained by northern insolation forcing alone. High resolution records of the precise timing and magnitude of climate change in the mid-latitudes of the Southern Hemisphere are strategic for understanding the forces driving global glacial cycles and identifying interhemispheric leads and lags in the climate system. Terrestrial archives (lake sediment) from southern New Zealand are ideal for such research because the region is sensitive to subtle changes in the circumpolar westerlies and supports distinct vegetation and chironomid (non-biting midge fly) ecological zones. Pollen and chironomids from this region have known relationships to temperature and can provide continuous, datable, quantitative estimates of terrestrial temperature change. This research has two primary goals: 1) to develop paleotemperature reconstructions for the western and eastern margins of the Southern Alps from two lakes located outside LGM moraine belts using pollen and chironomid temperature inference models, and 2) to determine the precise timing and duration of LGM climate changes for this location using detailed AMS radiocarbon dating. The project will provide a comprehensive paleoclimate data set that will be directly applicable to testing hypotheses about forcing mechanisms responsible for major climate changes.The proposed research will provide training opportunities for four undergraduate students per semester. It will develop and enhance collaborative ties between the University of Maine and several New Zealand institutions. Benefits to society include documenting the temporal and spatial extent and magnitude of climatological phenomena to better understand the LGM climate of the southern mid-latitudes and testing the viability of several hypotheses about mechanisms that drive ice age change.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。这项研究的目的是检验关于全球冰河时代驱动因素的主要假设是否可以解释南半球中纬度地区的气候变化。本研究利用连续的、同位素定年的古chironomid和花粉记录重建温度变化，确定了新西兰南阿尔卑斯山附近两个地点南部中纬度末次冰期极大期气候的时间、幅度和结构。关于冰河时代气候变化驱动因素的假设仍然模糊不清，因为最大冰河时代降温的时间和幅度（末次极大冰期，LGM）在南北半球之间似乎并不匹配。尽管南方太阳日照的强度和持续时间与北方不同，但北方太阳日照被认为是驱动南半球气候变化的原因。半球间LGM气候变化时间的明显不匹配不能仅用北方日照强迫来充分解释。南半球中纬度地区气候变化的精确时间和幅度的高分辨率记录对于理解驱动全球冰川循环的力量和确定气候系统中半球间的领先和滞后具有战略意义。新西兰南部的陆地档案（湖泊沉积物）是此类研究的理想选择，因为该地区对极地西风带的细微变化很敏感，并支持独特的植被和摇蚊（不咬人的蠓）生态区。该地区的花粉和摇虫与温度有已知的关系，可以提供陆地温度变化的连续、可测定的定量估计。本研究有两个主要目标：1)利用花粉和chironomid温度推断模型，从位于LGM冰碛带外的两个湖泊重建南阿尔卑斯西部和东部边缘的古温度；2)利用详细的AMS放射性碳定年技术，确定该地区LGM气候变化的精确时间和持续时间。该项目将提供一个全面的古气候数据集，将直接适用于测试关于主要气候变化的强迫机制的假设。本研究计划每学期为四名本科生提供训练机会。它将发展和加强缅因大学与几所新西兰机构之间的合作关系。对社会的好处包括记录气候现象的时空范围和强度，以更好地了解南中纬度地区的LGM气候，并测试有关驱动冰期变化机制的几个假设的可行性。