Doctoral Dissertation Research: Analyzing Tropical Alpine Glacier Dynamics During Middle-Holocene Warming

博士论文研究：分析中全新世变暖期间的热带高山冰川动力学

• 批准号: 1558358
• 负责人: Meredith Kelly
• 金额: $ 1.56万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558358&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Analyzing; Tropical

This doctoral dissertation research project will develop records of past glacier extents in one set of mountains in a tropical setting and will assess the sensitivity of glaciers in this and similar regions to changes in climatic conditions, such as alternate temperature and precipitation regimes. The project will provide new information and insights to address the degree to which alpine tropical glaciers are especially sensitive to changing climatic and other environmental conditions. The study region is one for which previous evidence seemed to indicate that alpine glaciers persisted during the middle of the Holocene Epoch, a period when evidence indicates that temperatures were as warm as or warmer than the present time period. The project helps to assess the sensitivity of these glaciers to warming temperatures in order to better ascertain both the timing and magnitude of past glacier fluctuations. By reconstructing past glacier extents in tropical regions like this, this project will improve basic understanding about the factors and dynamics that affect tropical glaciers as well as their sensitivity to a changing environment. The project also will provide information that will yield more accurate predictions of future glacier mass loss, project findings will facilitate planning and development activities in tropical regions, where glaciers provide crucial freshwater resources and ongoing glacier recession will impact directly the livelihoods and wellbeing of communities. The project will provide additional education and training benefits by engaging undergraduate students in some facets of the project and through presentations based on the project in elementary and secondary school classrooms in Vermont and New Hampshire. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.The ongoing retreat of tropical glaciers has been highlighted as one manifestation of contemporary change in environmental conditions around the Earth, but the sensitivity of these glaciers to projected future climate conditions is uncertain. Through this dissertation research project, the doctoral student will improve the understanding of tropical glacier response to warmer temperatures by determining the extents of glaciers in tropical eastern Africa over a period roughly 8,000 to 4,000 years ago, when the region was as warm as or warmer than at present. The student will use detailed geomorphic mapping and surface exposure dating of glacial deposits in the Rwenzori Mountains to determine glacier extents during the current interglacial period known as the Holocene Epoch, which extends from about 11,600 years ago to the present. She will employ a surface-exposure dating method that relies on measurements of the cosmogenic nuclide beryllium-10, which is produced in rock surfaces over time due to the influx of cosmic rays. The project will be the first study to develop a beryllium-10-based chronology of Holocene glacier extents in tropical eastern Africa. The student will compare the Rwenzori glacier chronology with records of temperature, precipitation, and glacier extents from other locations in tropical East Africa in order to assess the regional climate conditions and patterns of glacier fluctuations. These results will be compared with Holocene glacier extents in tropical South America. Determining whether glaciers across the global tropics fluctuated synchronously or asynchronously during the Holocene Epoch will provides information for evaluating the dynamics associated with changing global climatic conditions. Project results will advance efforts to model glaciers within future warming scenarios, thereby providing a means to test hypotheses about the possible mechanisms that transmitted climate signals across the globe during the Holocene Epoch.

该博士学位论文研究项目将在热带环境中在一组山脉中发展过去的冰川范围的记录，并将评估冰川在此和类似地区对气候条件变化（例如替代温度和降水状态）的敏感性。 该项目将提供新的信息和见解，以解决高山热带冰川对变化气候和其他环境条件特别敏感的程度。 该研究区域是以前的证据似乎表明在全新世时期中间的高山冰川持续存在，这一时期表明温度比当前时期温暖或温暖。 该项目有助于评估这些冰川对温暖温度的敏感性，以更好地确定过去冰川波动的时间和幅度。 通过重建像这样的热带地区的过去冰川范围，该项目将改善对影响热带冰川的因素和动态的基本理解，以及它们对不断变化的环境的敏感性。 该项目还将提供信息，这些信息将对未来的冰川群众损失进行更准确的预测，项目发现将有助于热带地区的计划和开发活动，冰川提供重要的淡水资源和持续的冰川衰退将直接影响谋生和社区的福祉。 该项目将通过在项目的某些方面和基于佛蒙特州和新罕布什尔州中小学教室中的项目的演讲来聘请本科生，从而提供额外的教育和培训益处。 作为博士学位论文研究改进奖，该奖项还将提供支持，使有前途的学生能够建立强大的独立研究职业。热带冰川的持续撤退已被强调，因为地球上环境环境环境条件中现代变化的一种表现，但是这些冰川的敏感性未来预测了未来的气候条件。 通过这项论文研究项目，博士生将通过确定热带东非热带冰川在大约8,000至4000年前的冰川的范围，以提高对温暖温度的反应的理解，当时该地区比目前的温​​暖或温暖。 学生将使用卢旺佐里山脉冰川沉积物的详细地貌图和表面暴露日期来确定当前被称为全新世时期的冰川间期间的冰川范围，该时期从大约11600年前延伸到现在。 她将采用一种表面曝光约会方法，该方法依赖于宇宙基因核素铍10的测量，该测量随着宇宙射线的流入而随着时间的流逝而在岩石表面产生。 该项目将是第一个在热带东非的全新世冰川范围内开发基于Beryllium-10的年代的研究。 该学生将比较Rwenzori冰川年表与热带东非其他位置的温度，降水和冰川范围的记录，以评估冰川波动的区域气候条件和模式。 这些结果将与热带南美的全新世冰川范围进行比较。 在全新世时期，确定全球热带地区的冰川是否同步或异步波动，将提供信息，以评估与变化的全球气候条件相关的动态。 项目结果将促进在未来的变暖场景中对冰川进行建模的努力，从而提供一种方法来测试有关在全新世时期期间在全球范围内传播气候信号的可能机制的假设。