Dust transport and deposition in the American West: a record of climate and land-use change from the Upper Fremont Glacier, Wind River Range, Wyoming

a.对项目更广泛意义和重要性的非技术解释人类对气候的影响是全球性的，如通过大气温室气体，也有区域性的，如土壤扰动带来的灰尘。在过去的几十年里，美国西南部和科罗拉多高原的农业和牲畜放牧等人类活动的增加与更多的粉尘产生和沉积有关。在季节性和年度的基础上，沙尘产生的变化可以从山雪的数量中看到，这些变化被保存在跨越过去几百年的高山冰川的冰中。到达冰原或冰川的沙尘颗粒来源的变化可以表明沙尘产生、来源和大气输送途径的变化，因此是土地利用和气候变化的宝贵指标。该项目将研究来自上弗里蒙特冰川（怀俄明州风河山脉）的冰芯中北美尘埃的半连续记录。这个冰芯跨越了农业和工业革命，并将评估美国西部从小冰期结束（公元1350-1850年）到今天的土地利用、气候和天气变化是如何被尘埃成分变化记录下来的。该项目的技术描述本研究将利用怀俄明州风河山脉上弗里蒙特冰川的冰，评估人为活动导致的大气尘埃水平的变化。本研究的主要目的是测量气溶胶矿物粉尘的物理和化学特征，以便建立美国西部从小冰期结束到工业革命以及美国农业急剧扩张的粉尘负荷和来源变化的记录。来自上弗里蒙特冰川的现有冰芯将用于测量尘埃量的变化。晶粒尺寸，微量元素浓度和放射性同位素组成（Sr, Nd, Hf）也将被确定。北美的潜在粉尘来源将从空间分布的地点收集并进行化学表征。将比较冰芯和实地收集的来源地区的数据，以确定粉尘数量和来源的变化，并检查其与区域气候和土地利用变化的关系。

a. Non-technical explanation of the project's broader significance and importanceHuman influences on climate are global, such as through atmospheric greenhouse gases, and also regional, from dust that spreads from soil disturbance. Increased human activity such as agriculture and livestock grazing in the American southwest and the Colorado Plateau during the past several decades has been correlated with greater dust production and deposition. Changes in dust production on a seasonal to annual basis can be seen in the amount incorporated into mountain snow and these changes are preserved in the ice of alpine glaciers that span the last several hundred years. Variations in the origin of dust particles reaching an ice sheet or glacier can indicate a shift in dust production, sources, and atmospheric transport pathways, and are therefore valuable indicators of land use and climate change. This project will examine a semi-continuous record of North American dust in an ice core from the Upper Fremont Glacier (Wind River Range, Wyoming). This ice core spans the Agricultural and Industrial Revolution and will assess how changing land use, climate and weather in the western United States from the end of the Little Ice Age (1350-1850 AD) to today is recorded by dust compositional changes.b. A technical description of the projectThis research will evaluate the change in atmospheric dust levels due to anthropogenic activities using ice from the Upper Fremont Glacier in the Wind River Range, Wyoming. The primary objective of this research is to measure the physical and chemical characteristics of aerosol mineral dust in order to construct a record of dust load and provenance variability in the American West from the end of the Little Ice Age through the Industrial Revolution and into the dramatic expansion of agriculture across the United States. An existing ice core from the Upper Fremont Glacier will be used to measure variations in the dust amount. Grain size, trace element concentration, and radiogenic isotopic compositions (Sr, Nd, Hf) will also be determined. Potential sources of the dust in North America will be collected from spatially distributed sites and chemically characterized. The data from the ice core and field-collected source areas will be compared to determine the variations in dust amounts and sources, and to examine the relationship to regional climate and land-use changes.