Doctoral Dissertation Research: A Long-Term Paleoclimate Perspective on the Changing Hydroclimatology of the Bear River Basin

博士论文研究：熊河流域水文气候变化的长期古气候视角

• 批准号: 0926715
• 负责人: Andrea Brunelle
• 金额: $ 0.89万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0926715&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Long; Term

Paleoclimate records from sedimentary archives provide baseline information about the long-term range of natural climate variability in a region. The Bear River Basin, located at the intersection of Utah, Idaho, and Wyoming, is an important area providing water resources for three states. Future population growth in the basin and along the Wasatch Front is going to increasingly depend on the availability of water in coming years. Long-term variability in Bear River water resources is not well understood due to relatively short instrumental datasets, yet resource managers and policy makers will need a long-term perspective to plan future development to avoid creating future political conflicts or endangering sensitive wildlife habitat in areas such as a nearby migratory bird refuge. Paleoclimate data extracted from lake sediments and speleothems from the Bear River Range, a primary hydrologic recharge area for the Bear River, will provide a much needed long-term record of hydroclimate and vegetation in the river basin. Pollen, charcoal, magnetic susceptibility, and loss-on-ignition data will be extracted from sediment cores collected from a small glacial lake. These data will provide a record of climate and vegetation in the area over approximately the last 13,000 years. Stable carbon and oxygen isotope ratios from a stalagmite in nearby Minnetonka Cave will also be used to develop an independent climate and vegetation history at multi-decadal resolution. Speleothem records and lacustrine records have both been used frequently to extract paleoclimate proxy data from locations throughout the world. However, a direct comparison of records obtained from the two archives is often difficult due to relatively large distances between records, or significantly different topographic settings. This study will compare a speleothem record and a lake record located less than 10km from one another. Furthermore, the cave and the lake are located at similar elevations and both lie in valleys located on the east side of the main ridgeline. Thus, conditions at the two sites can be assumed to have been similar throughout the length of the overlapping records, allowing a direct comparison of archive sensitivity.The results of this project will provide context for understanding historic Bear River water resource inventories. In addition, due to the location of the Bear River range along an observed regional climate boundary, the paleoclimate record from the region will provide a long-term record of past boundary migration and the resultant effects on local hydroclimatic conditions and biogeography. Comparing and contrasting the timing and nature of past climate changes in the Bear River Basin with locales to the north and south will help refine the spatial distribution of areas that are predicted to have increased/ decreased precipitation in the future, as a result of global climate change. This study will also provide a methodological contribution to the field of paleoclimatology by providing insights into any signal preservation biases that may exist in lake and cave deposit records. 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.

沉积档案中的古气候记录提供了一个地区自然气候变化长期范围的基线信息。熊河流域位于犹他州、爱达荷州和怀俄明州的交汇处，是为三个州提供水资源的重要地区。未来几年，该盆地和沿着瓦萨奇前线的人口增长将越来越多地取决于水的供应。由于仪器数据集相对较短，熊河水资源的长期变化还没有得到很好的理解，但资源管理者和政策制定者将需要一个长期的视角来规划未来的发展，以避免造成未来的政治冲突或危及附近候鸟避难所等地区敏感的野生动物栖息地。从熊河山脉（熊河的主要水文补给区）的湖泊沉积物和洞穴沉积物中提取的古气候数据将提供流域水文气候和植被的急需长期记录。花粉，木炭，磁化率和烧失量的数据将提取从一个小冰川湖收集的沉积物芯。这些数据将提供该地区近13 000年来的气候和植被记录。从附近明内通卡洞穴的石笋中获得的稳定的碳和氧同位素比率也将用于在几十年分辨率下开发独立的气候和植被历史。洞穴沉积物记录和湖泊记录都经常被用来提取来自世界各地的古气候代用数据。然而，直接比较从两个档案馆获得的记录往往是困难的，因为记录之间的距离相对较大，或者地形设置有很大的不同。本研究将比较相距不到10公里的洞穴沉积物记录和湖泊记录。此外，洞穴和湖泊位于相似的海拔高度，都位于主山脊线东侧的山谷中。因此，在这两个网站的条件可以被假定为已在整个重叠记录的长度相似，允许档案sensitivity. Results的直接比较，这个项目将提供了解历史的熊河水资源清单的背景。此外，由于熊河山脉的位置沿着观察到的区域气候边界，该地区的古气候记录将提供过去边界迁移的长期记录，以及对当地水文气候条件和地理的影响。将熊河流域过去气候变化的时间和性质与北部和南部的地区进行比较和对比，将有助于改进由于全球气候变化而预测未来降水增加/减少的地区的空间分布。这项研究还将提供一个方法的贡献，古气候学领域提供的任何信号保存偏见，可能存在于湖泊和洞穴存款记录的见解。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。