Collaborative Research: A High-sensitivity Beryllium-10 Record from an Ice Core at South Pole

该项目将从南极冰芯获取铍-10(10Be)浓度的测量结果。铍元素的一种同位素，10Be，是由从太空进入地球大气层的高能质子(宇宙射线)在大气中产生的。它通过沉淀或在雨雪中觅食而从大气中移走。因此，南极雪中10Be的浓度反映了大气中10Be的产生率。由于南极上空10Be的产生速度主要取决于太阳磁场的强度，因此对南极冰芯中10Be的测量将提供太阳活动变化的记录。南极冰芯底部将达到4万年的年龄。该项目将以年分辨率测量过去100年和更遥远过去的选定时期的10Be，例如17世纪末没有观测到太阳黑子的蒙德极小期，或大约20,000年前的最后一次冰冷时期。一个气候模型可以模拟10Be在大气中的产生，它在大气中的传输，以及它在南极雪面上的沉积，将被用来帮助利用10Be数据来确定太阳活动过去从十年到千年的变化，并进而从一个新的角度评估太阳在地球气候中的作用？S从一个新的角度。地球大气中10Be的产生是宇宙射线对大气中氧和氮的溅射造成的。高纬度地区的宇宙线变化主要受太阳变化的影响。因此，来自冰芯的10Be的时间序列记录对于得出太阳活动随时间的变化很重要，这是理解气候变化的基础。10Be向冰面的沉积也受到大气环流和沉积过程变化的影响，南极是减小大气环流变化对10Be沉积影响的最佳可用位置。到目前为止，南极只有一项10Be的记录；这一记录被广泛用于气候模型中的太阳强迫估计，但只涵盖了最后一个千年，并在CE1982年结束。我们将在南极1500米、40000年长的冰芯中获得10Be浓度的测量结果。这将把现有的记录进一步向前和向后延伸到现在，提供与太阳和气候变异性的现代仪器记录的重叠。将在特定的感兴趣区域进行高分辨率(每年至每两年)测量，包括最近100年、蒙德极小期(CE1650-1715)和最后一次冰川极值期。这些新颖的数据将与气候模型实验结合使用，这些实验包含了10Be的产生、运输和沉积物理。综合起来，数据和模型将产生大气10Be的最新记录，从而产生太阳活动的最新记录。

This project will acquire measurements of the concentration of beryllium-10 (10Be) from an ice core from the South Pole, Antarctica. An isotope of the element beryllium, 10Be, is produced in the atmosphere by high-energy protons (cosmic rays) that enter Earth's atmosphere from space. It is removed from the atmosphere by settling or by scavenging by rain or snowfall. Hence, concentrations of 10Be in snow at the South Pole reflect the production rate of 10Be in the atmosphere. Because the rate of production of 10Be over Antarctica depends primarily on the strength of the Sun's magnetic field, measurements of 10Be in the South Pole ice core will provide a record of changes in solar activity. The South Pole ice core will reach an age of 40,000 years at the bottom. The project will result in measurements of 10Be at annual resolution for the last 100 years and selected periods in the more distant past, such as the Maunder Minimum, a period during the late 17th century during which no sunspots were observed, or the last glacial cold period, about 20,000 years ago. A climate model that can simulate the production of 10Be in the atmosphere, it's transport through the atmosphere, and its deposition at the snow surface in Antarctica will be used to aid in using the 10Be data to determine past changes in solar activity from decadal to millennial scale, and in turn to evaluate the role of the Sun in Earth?s climate from a new perspective.The production of 10Be in Earth's atmosphere results from the spallation of oxygen and nitrogen in the atmosphere by cosmic rays. Cosmic ray variations in the high latitudes are primarily modulated by solar variability. Time-series records of 10Be from ice cores are therefore important for deriving variations in solar activity through time, which is fundamental to understanding climate variability. Deposition of 10Be to the ice surface is also influenced by variability in atmospheric circulation and deposition processes, and South Pole is the best available location for minimizing the influence of variable atmospheric circulation on 10Be deposition. To date, only one record of 10Be exists from South Pole; that record is widely used in solar forcing estimates used in climate models, but covers only the last millennium and ends in CE 1982. We will obtain 10Be concentration measurements in a 1500-m, 40000-year long ice core from the South Pole. This will extend the existing record both further back in time and forward to the present, providing overlap with the modern instrumental record of solar and climate variability. High resolution (annual to biannual) measurements will be made in targeted areas of interest, including the last 100 years, the Maunder Minimum (CE 1650-1715), and the last glacial maximum. The novel data will be used in conjunction with climate model experiments that incorporate 10Be production, transport, and deposition physics. Together, data and modeling will create an updated record of atmospheric 10Be production and hence of solar activity.