Varved-sediment Records of Rapid Climatic Change About 10,700 Years Ago

新仙女木气候事件在地球历史上很重要，因为它是在没有任何已知的直接外部强迫的情况下发生的气候变化的快速逆转。因此，它是地球内部反馈导致气候变化的最好例子。目前，世界上许多地方对新仙女木降温事件的影响知之甚少。本研究的目的是确定这一事件在明尼苏达州和威斯康星州的时间和气候影响。PI将使用每年的层压湖沉积物来精确确定这种植被变化的时间。然后，PI将评估岩心中的花粉，以确定伴随气候事件的温度和降水变化。考虑到内部反馈改变未来温室效应的可能性，为了更好地预测未来的气候变化，研究过去的这个例子是很重要的。

The Younger Dryas climate event is important in earth history because it is a rapid reversal in climate change that occurred without any known, direct external forcing. Thus it is the best example of the earth's internal feedbacks causing climate change. At present, the effects of the Younger Dryas cooling event are poorly known in many parts of the world. The purpose of this research is to determine the timing and climatological effects of this event in Minnesota and Wisconsin. The PI will use annually-laminated lake sediments to precisely date the timing of this vegetation change. Then the PI will evaluate the pollen in the cores to determine the changes in temperature and precipitation that accompanied the climatic event. Given the possibility of internal feedbacks altering the effects of future greenhouse warming, it is important to study this past example in order to better predict future changes in climate.