Sources and oceanic paths of large meltwater discharge events and their roles in abrupt holocene climatic events

大规模融水排放事件的来源和海洋路径及其在全新世突发气候事件中的作用

• 批准号: 341997-2007
• 负责人: Levac, Elisabeth
• 金额: $ 1.59万
• 依托单位: Bishop's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=482399
• 关键词: Sources; oceanic; paths; large; meltwater

My research program will provide a better understanding of abrupt climatic changes that occurred during the last 11,000 years, a topic currently of interest to the United Nations Intergovernmental Panel on Climate Change (IPCC), in view of the potentially serious implications such abrupt changes have on human societies. These events are difficult to replicate using numerical climate models, so paleoclimatic proxy data is indispensable to their study. It is not possible now to identify the primary cause of abrupt climatic events among meltwater discharges, natural climatic variability, shifts in oceanic currents, and solar influence. Since there is not even consensus about the source and routing (path) of some large meltwater releases that occurred during the last deglaciation, it is not possible to confirm or rule out their role in abrupt climate cooling events. This project will focus on meltwater source and paths believed to have caused such severe cooling events as the Younger Dryas and the Preboreal oscillation. I will verify if large amounts of meltwater from glacial Lake Agassiz (and/or other glacial lakes) were discharged through the St. Lawrence River between 11,000 and 7000 years ago. In order to do so, I will study high resolution marine sediment cores from strategic locations to detect any meltwater releases through that route. Sea surface temperature and salinity will be reconstructed using dinoflagellate cysts data and transfer functions. These paleoceanographic records will also be used to document the frequency and amplitude of natural climatic variability in that region. Knowing the frequency of these oscillations might help to identify their causes and will contribute to the better knowledge of our climate system.

我的研究项目将更好地理解过去11000年间发生的气候突变，鉴于这种突变对人类社会的潜在严重影响，这是联合国政府间气候变化专门委员会（IPCC）目前感兴趣的话题。这些事件很难用数值气候模式来复制，因此古气候代理数据对他们的研究是不可或缺的。现在还不可能在融水排放、自然气候变率、洋流变化和太阳影响中确定突发气候事件的主要原因。由于对上次冰期期间发生的一些大型融水释放的来源和路径（路径）甚至没有达成共识，因此不可能确认或排除它们在气候突然变冷事件中的作用。该项目将重点研究被认为导致新仙女木期和前寒武纪振荡等严重降温事件的融水来源和路径。我将验证在11000年到7000年前，阿加西冰川湖（和/或其他冰川湖）的大量融水是否通过圣劳伦斯河排放。为此，我将研究战略地点的高分辨率海洋沉积物岩心，以检测通过该路线释放的任何融水。利用鞭毛藻囊数据和传递函数重建海表温度和盐度。这些古海洋学记录还将用于记录该地区自然气候变化的频率和幅度。了解这些振荡的频率可能有助于确定其原因，并有助于更好地了解我们的气候系统。