Rocky Mountain snowpack changes and their hydrologic consequences during the Holocene

美国西部山间高海拔积雪的损失给该地区带来了重大的社会风险，气温升高可能会永久性地减少积雪量，并影响河流和溪流的基流。这项研究着眼于湖泊有机沉积物中代用品记录的过去气候的地质记录，并利用这些信息提供该地区未来水资源将如何应对气候变化的观点。过去的水循环记录通过分析过去影响积雪的温度和降水变化的组合，为最近的变化提供了长期的背景。 这种重建可以帮助预测未来的变化。这项研究的结果将传达给从公共机构到该地区居民的广大利益攸关方。研究小组将与怀俄明州大学地质博物馆和媒体机构，如怀俄明州公共广播电台合作，通过采访和媒体展示结果。 该项目将在怀俄明州大学和美国林务局的一个长期监测点建立研究和教育能力。该项目将使用湖泊沉积物生物标志物和矿物分析的新组合，以限制对气候变化敏感的三个落基山脉小流域在过去11,000年中积雪、温度、径流、蒸发和灰尘沉积的变化。具体而言，该研究将开发三个新的C29正烷烃（叶蜡）和C23正烷烃（水生）氢同位素记录，沿着三个湖泊沉积物矿物学的X射线衍射记录，以及三个可比较的分支GDGT（甘油二烷基甘油四醚）湖泊水温记录。这些代理的组合将提供一个多代理的角度来看，在落基山积雪的变化，并用于评估气候和水文因素参与的代理记录。这样，这些不同类型的数据的结合将丰富对美国西部水资源变化的理解，以及这些变化背后的机制。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Loss of high-elevation snowpack in the intermountain western US poses major societal risks for the region, where increased temperatures may permanently reduce snowpack amounts and impact baseflow in rivers and streams. This research looks towards the geological record of past climates recorded by proxy in organic sediments in lakes and uses this information to provide a perspective on how future water resources in the region will respond to climate change. The past records of the water cycle provide this long-term context to recent changes by analyzing the combinations of temperature and precipitation changes that have impacted snowpack in the past. Such reconstructions can help anticipate future changes. The results of this research will be communicated to broad audiences of stakeholders from public agencies to residents of the region. The research team will work with the University of Wyoming Geology Museum and media outlets, such as Wyoming Public Radio, to present the results through interviews and media. Research and education capacity will be built at the University of Wyoming and at a long-term monitoring site maintained by the US Forest Service.This project will use a novel combination of lake sediment biomarker and mineral analyses to constrain the changes in snowpack, temperature, runoff, evaporation, and dust deposition over the past 11,000 years in three small Rocky Mountain watersheds that are sensitive to climate change. Specifically, the research will develop three new C29 n-alkane (leaf wax) and C23 n-alkane (aquatic) hydrogen isotope records, along with three x-ray diffraction records of lake sediment mineralogy, and three comparable branched GDGT (glycerol dialkyl glycerol tetraether) records of lake water temperature. The combination of these proxies will provide a multi-proxy perspective on changes in Rocky Mountain snowpack, and use to assess climatological and hydrological factors involved in the proxy records. In so doing, the combination of these different types of data will enrich the understanding of the variability of water resources in the western US and the mechanisms underlying these changes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.