The Last Glacial Termination in Southern Middle Latitudes

这一壮观的终结标志着上一个主要冰河时代的结束，代表着地球近代史上最大、最快的自然气候变化。确定导致这种终止的条件和过程需要监测全球最后一次冰川/间冰期过渡的敏感古气候指标的详细年表。这笔赠款将在南半球中纬度地区建立新西兰南阿尔卑斯山从上一次冰盛期到今天的S条件下冰量减少的年表。我们的年表将基于最新开发的最先进的10Be表面暴露测年，这些测年是在这次减少期间产生的冰川地貌。这笔赠款将确定南极退冰期信号是否延伸到南半球的中纬度，从而对首席研究员发表在《科学》杂志上的最近的一项假说进行了检验。这一假说假定，夏季上升的阳光引发了北半球的大冰盖，产生了自我维持的冰山洪流，并将水融化到北大西洋，导致北方寒冷的气候条件改变了全球经向温度梯度，进而调节了全球主要的纬向风系统。南半球西风向极地移动和/或加强使南半球从中纬度到南极洲变暖，并通过南大洋上升流向大气排放足够的二氧化碳，以维持世界各地的间冰期条件。由于新西兰冰川位于中纬度，靠近南大洋外边界，这一假说预测，它们的体积损失应该与南极变暖脉冲相关，并且应该与淡水流入北大西洋引发的北部冰川相反。这项研究将确定新西兰南部阿尔卑斯山的冰川衰退的日期，S因此验证了这一预测。当今的全球变暖是头条新闻。但科学家们仍然没有完全了解导致全球变暖的潜在机制，这种巨大的全球变暖结束了上一个冰河时代，并产生了过去11,700年的间冰期条件，在此期间，人类文明和人口得到了发展。该研究小组提出了一个假设，说明这种巨大的变暖是如何实现的。这笔赠款将产生有关南半球事件发生时间的知识，以检验这一假设。这项测试涉及识别伴随着半球之间温度梯度变化的风带和海洋环流的变化。预计很快半球间温度梯度也会发生变化，因为大气中二氧化碳的上升预计会使南半球变暖的程度低于北半球。因此，通过研究过去的大变暖，我们可能能够预测在正在进行的全球变暖期间，这种变化可能会如何发生。

The spectacular termination that marked the end of the last major ice age represents the largest and most rapid natural climate change in Earth's recent history. Identifying the conditions and processes that led to this termination requires detailed chronologies of sensitive paleoclimate proxies that monitor the last glacial/interglacial transition across the globe. This grant will develop such a chronology in the middle latitudes of the Southern Hemisphere for the reduction of ice volume in the Southern Alps of New Zealand from the last glacial maximum to today?s conditions. Our chronology will be based on newly developed state-of- the-art 10Be surface-exposure dating of glacial landforms produced during this reduction. This grant will determine if the Antarctic deglacial signal extents to middle latitudes of the Southern Hemisphere, thus setting up a test of a recent hypothesis that the Principal Investigator published in Science. The hypothesis posits that large Northern Hemisphere ice sheets, triggered by rising summer sunshine, produced a self-sustaining flood of icebergs and melt water into the North Atlantic, leading to cold northern stadial conditions that altered the global meridional temperature gradients which in turn regulated the major global zonal wind systems. A poleward shift and/or intensification of the Southern Hemisphere westerlies warms the Southern Hemisphere from middle latitudes to Antarctica and purges enough CO2 to the atmosphere by Southern Ocean upwelling to maintain interglacial conditions worldwide. Because New Zealand glaciers lie in middle latitudes near the outer boundary of the Southern Ocean, this hypothesis predicts that their volume loss should correlate with the Antarctic warming pulse and should be in antiphase with the northern stadial triggered by freshwater influx into the North Atlantic. This research will date ice recession in New Zealand?s Southern Alps and thus test this prediction.Present-day global warming is front-page news. But scientists still do not fully understand the underlying mechanisms that caused the great global warming that ended the last ice age and produced the interglacial conditions of the last 11,700 years, during which human civilization and population has developed. The team has developed a hypothesis of how this great warming was achieved. The grant will produce knowledge of the timing of Southern Hemisphere events to test the hypothesis. This test involves recognition of changes in wind belts and ocean circulation that accompany a shift in the temperature gradient between hemispheres. A shift in the interhemispheric temperature gradient is also expected shortly, as rising atmospheric CO2 is predicted to warm the Southern less than the Northern Hemisphere. Thus, by studying the past great warming, we may be able to anticipate how such changes may occur during the ongoing global warming.