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

我的研究计划将更好地了解过去11,000年间发生的气候突然变化，鉴于这种突然变化对人类社会可能产生的严重影响，这是联合国政府间气候变化专门委员会(IPCC)目前感兴趣的一个主题。这些事件很难用数值气候模型来复制，因此古气候替代数据对于它们的研究是不可或缺的。现在还不可能在融水排放、自然气候变化、洋流变化和太阳影响中确定突然气候事件的主要原因。由于对上一次冰川消融期间发生的一些大型融水释放的来源和路线(路径)甚至没有达成共识，因此无法确认或排除它们在气候突然变冷事件中的作用。该项目将专注于融水来源和路径，据信这些融水来源和路径导致了像年轻仙女木和前北冰洋振荡这样的严重冷却事件。我将核实冰川湖阿加西湖(和/或其他冰川湖)的大量融化水是否在11000至7000年前通过圣劳伦斯河排放。为了做到这一点，我将研究战略位置的高分辨率海洋沉积物岩心，以探测通过这条路线释放的任何融水。将利用甲藻包囊数据和传递函数重建海表面温度和盐度。这些古海洋学记录还将被用来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它们的原因，并有助于更好地了解我们的气候系统。

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.