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

合作研究：来自南极冰芯的高灵敏度铍 10 记录

• 批准号: 1443144
• 负责人: Eric Steig
• 金额: $ 20.97万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443144&HistoricalAwards=false
• 关键词: Collaborative; Research; sensitivity; Beryllium; 10

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.

该项目将从南极南极的冰芯中获取铍-10（10be）浓度的测量。 元素铍的同位素是10BE，是由高能质子（宇宙射线）从太空进入地球大气的高能质子（宇宙射线）产生的。 它通过沉降或通过降雨或降雪清除而从大气中取出。 因此，南极在雪中浓度的浓度反映了大气中10BE的产量。 由于南极洲10BE的生产率主要取决于太阳磁场的强度，因此南极冰芯中10BE的测量结果将提供太阳能活动变化的记录。 南极冰芯将达到底部40，000年。 该项目将导致过去100年的年度分辨率的10BE测量，并在更遥远的过去（例如Maunder Minimum）中选择的时期，在17世纪后期未观察到太阳早期或最后一次冰川冷的时期时期，大约20，000年前。 一个可以模拟大气中10BE产生的气候模型，它是通过大气传输的，其在南极洲的雪表面的沉积将用于使用10BE数据来确定从际交往到千禧年的太阳能活动的过去变化从新的角度来看，尺度并评估太阳在地球气候中的作用。地球大气中10BE的产生是由于宇宙射线在大气中氧气和氮在大气中的剥落而产生的。 高纬度的宇宙射线变化主要是由太阳变异性调节。因此，来自冰芯的10BE的时间序列记录对于通过时间来得出太阳活动的变化很重要，这对于理解气候变异性至关重要。 10BE沉积到冰面也受大气循环和沉积过程的变化的影响，而南极是最大程度地减少可变大气环流对10BE沉积的影响的最佳位置。迄今为止，只有一个10be的记录来自南极；该记录被广泛用于气候模型中使用的太阳能强迫估计，但仅涵盖了最后一个千年，并在1982年CE结束。我们将在南极从1500 m，40000年的冰芯获得10BE浓度测量。 这将扩展到现有的记录，既可以返回到现在，也可以扩展到现在，从而与现代的太阳和气候变异性记录重叠。高分辨率（年度至一年一度）测量将在目标的目标区域进行，包括最近100年，最低限度（CE 1650-1715）和最后的冰川最大值。新数据将与包含10BE生产，运输和沉积物理的气候模型实验结合使用。一起，数据和建模将创建大气10BE生产以及太阳活动的更新记录。