RUI: Collaborative Research: Glaciation and Climate Change in the Rocky Mountains During the Last Glacial Maximum and the Subsequent Deglaciation

RUI：合作研究：末次盛冰期和随后的冰消期期间落基山脉的冰川作用和气候变化

• 批准号: 1024852
• 负责人: Benjamin Laabs
• 金额: $ 8.95万
• 依托单位: SUNY College at Geneseo
• 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: 2010-09-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1024852&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Glaciation; Climate

Mountain glaciers were numerous in the Rocky Mountains of western North America during the last Pleistocene glaciation, and the geologic record of these glaciers provides dramatic evidence of climatic changes during and following the Last Glacial Maximum. This research will build upon and augment the Pleistocene mountain glacial chronologies in the U.S. Rocky Mountain region, and use these chronologies to model past climate changes. The project uses both field and analytical methods to address two broad objectives: (1) to determine the changes from modern climate that would be necessary to sustain Rocky Mountain glaciers at their last Pleistocene maximum extents, along a transect from northern Montana to south-central New Mexico, and (2) to determine the timing and rate of subsequent ice recession, and the magnitudes and rates of climate change necessary to drive that recession. The first objective involves additional glacial mapping and chronology in eight study areas, making use of cosmogenic beryllium-10 surface-exposure dating to constrain the timing and extent of glaciers during Last Glacial Maximum. A numerical model of glacier mass balance and ice flow will allow determination of the character and magnitudes of climatic change sufficient to produce the observed glacial extents. The second objective involves additional surface-exposure dating in four of the eight study areas to constrain the timing and rates of ice recession following its maximum stand, and to allow modeling of the climate changes that caused the recession. The results of this research will include a regional synthesis of glacier-climate reconstructions for the last Pleistocene glaciation and the subsequent deglaciation, an assessment of the climatic significance of the apparent variability in the timing of the Last Glacial Maximum, and an improvement in the chronology of mountain glacier movements.This application of high-resolution glacier modeling and cosmogenic-radionuclide dating methods will provide insight into the history of climate change in the Rocky Mountain region. The time interval of interest is the Last Glacial Maximum (the interval of maximum global ice volume) and the subsequent transition to the present warm period, the latter occurring over approximately 6000 years. This transition was an interval of major global warming, during which substantial changes in atmospheric circulation occurred in the western United States in response to shrinking ice sheets, increased incoming solar radiation, and rising atmospheric carbon dioxide levels. Such changes in airflow undoubtedly brought about changes in regional precipitation patterns, as is suggested by paleoclimate models. The results of this research will assess the accuracy of such models in representing precipitation patterns of the past, and may also provide insight into the accuracy of model predictions of future precipitation changes in the Rocky Mountains region, an area where demand for limited water resources continues to grow.

在最后一个更新世冰川期间，北美西部洛矶山脉的山地冰川无数，这些冰川的地质记录为最后一次冰川最大值期间和之后的气候变化提供了巨大的证据。这项研究将基于美国落基山地区的更新世山冰川年代的基础，并使用这些时间表来对过去的气候变化进行建模。 The project uses both field and analytical methods to address two broad objectives: (1) to determine the changes from modern climate that would be necessary to sustain Rocky Mountain glaciers at their last Pleistocene maximum extents, along a transect from northern Montana to south-central New Mexico, and (2) to determine the timing and rate of subsequent ice recession, and the magnitudes and rates of climate change necessary to drive that recession.第一个目标涉及在八个研究区域中的其他冰川图和年表，利用宇宙生成氏芽孢杆10的表面暴露，以限制上一次冰川最大值期间冰川的时间和程度。冰川质量平衡和冰流的数值模型将允许确定气候变化的特征和大幅面，足以产生观察到的冰川范围。第二个目标涉及在八个研究区域中的四个中的四个表面曝光日期，以限制其最大立场后的冰衰退的时间和速度，并允许对导致经济衰退的气候变化进行建模。这项研究的结果将包括冰川气候重建的区域综合，用于上次更新世冰川和随后的退化，评估上次冰川最大值的明显时间变化的气候意义，以及在山地冰川运动时期的改进。洞悉落基山地区气候变化的历史。感兴趣的时间间隔是最后的冰川最大值（最大全球冰量的间隔）和随后到当前温暖期的过渡，后者发生在大约6000年中。这种过渡是全球重大变暖的间隔，在此期间，美国西部大气循环发生了很大的变化，以响应冰盖缩小，增加的太阳辐射增加以及大气中二氧化碳水平上升。正如古气候模型所建议的那样，气流的这种变化无疑会导致区域降水模式的变化。 这项研究的结果将评估此类模型在代表过去的降水模式方面的准确性，并且还可以洞悉落基山地区未来降水量变化的模型预测的准确性，落基山地区对水资源有限的需求持续增长。