The ABN1314_prelim_database_010416 - black carbon, electrical conductivity, glacial ice aerosol composition, hydrogen peroxide, particle count in glacial ice

The ABN1314_prelim_database_010416 is the measured liquid conductivity (liq_cond), black carbon (BCconc), particles (partcntm), acidity (hno3), hydrogen peroxide (h2o2), oxygen isotopes (d18O), deuterium isotopes (dD), sodium (Na), magnesium (Mg), sulphur (S), calcium (Ca) and strontium (Sr) data for the 'ABN' (Aurora Basin North) ice core (ABN1314) collected during the Antarctic 13/14 season.Over six weeks, between December 2013 and January 2014, 24 scientists in two field teams drilled a 303 m long ice core at the remote site. The goal was to fill a major gap in an array of 2,000 year ice core climate records distributed across Antarctica. Two smaller drills were used to recover two shallow ice cores 116 m and 103 m long spanning the past 800 to 1,000 years. Ancient air samples extracted from the boreholes, as well as from bubbles trapped in the ice cores, help us to examine changes in atmospheric composition over time. The Aurora Basin drill site is about 550 km from Australia’s Casey station.Dr Mark Curran, from the Australian Antarctic Division, is the Science Leader for the project.The ice cores will be used to measure a range of chemical constituents to reconstruct past climate.The Aurora Basin team will use a field-based Picarro laser spectrometer to measure water (H2O) isotopes (different nuclear forms of oxygen and hydrogen) in the 400 m core. Ice formed under cooler conditions, for example, will contain more 16O while ice formed under warmer conditions will contain more of the heavier isotope, 18O. These isotope changes are mostly influenced by temperature, enabling scientists to infer what the temperature was when the snow originally fell. By measuring these isotopes on site, rather than in a laboratory on their return, the scientists will have a 2,000 year temperature record as soon as they leave the field.Samples from the core will also be cut for later laboratory analysis of methanesulphonic acid (MSA). MSA is produced from the oxidation in the atmosphere of dimethylsulphide, which is itself produced by certain species of phytoplankton in the Southern Ocean. The amount of MSA in an ice core is related to the maximum extent of sea ice in the region — when there is more sea ice there is more phytoplankton activity following sea ice decay and therefore more MSA production.One of the 120 m cores will be used purely for sulphur isotope analysis to assess the volcanic ‘forcing’ (impact) on natural climate variation over time. Similarly, carbon dioxide concentrations in the ice will be measured to assess the greenhouse gas forcing on natural climate variation while beryllium-10 measurements will give an indication of solar forcing.Scientists from the Desert Research Institute in the United States will produce much of the fine detail climate record by measuring a range of chemical species and elements in the 400 m core. These include dust tracers such as magnesium and iron, ash from fires, seawater tracers such as sodium and bromine, and volcanic tracers such as copper and cadmium. These analyses will help date the ice core and provide information about natural aerosols and pollution levels in the recent era.Finally, the team will extract air from the ‘firn’ ice at the top of one of the 120 m ice cores. Firn ice is unconsolidated ice that contains a lot of air space, unlike consolidated ice where air is trapped in bubbles. The extracted air will be ‘fresher’ or more modern than air trapped deep within the ice core and will provide a record of gas concentrations over recent decades (including carbon dioxide, carbon monoxide, methane, oxygen and nitrogen). This will help scientists better understand the carbon cycle and anthropogenic changes.Aurora Basin is the ideal site for the research as it has sufficient snowfall of about 13 cm of ice per year; enough to provide the first record of year-to-year changes over the past 2000 years in this region of the continent.Aurora Basin also harbours some of the deepest ice in Antarctica – over 3 km thick. Ice this thick could be over one million years old. Data collected during the drilling of the 2000 year ice core may help scientists locate a suitable site for drilling this million year old ice core.

ABN1314_prelim_database_010416数据集为南极13/14科考季采集的ABN（极光盆地北，Aurora Basin North，ABN1314）冰芯（ice core）的实测数据，涵盖液态电导率（liquid conductivity，缩写liq_cond）、黑碳（black carbon，缩写BCconc）、颗粒物浓度（particle count mass，缩写partcntm）、硝酸（nitric acid，缩写hno3）、过氧化氢（hydrogen peroxide，缩写h2o2）、氧同位素（oxygen isotopes，缩写d18O）、氘同位素（deuterium isotopes，缩写dD）、钠（sodium，缩写Na）、镁（magnesium，缩写Mg）、硫（sulphur，缩写S）、钙（calcium，缩写Ca）以及锶（strontium，缩写Sr）等参数。
2013年12月至2014年1月的六周时间内，两支野外科考团队共24名科学家在该偏远点位钻取了一根总长303米的冰芯。本次科考的核心目标是填补横贯南极大陆的2000年冰芯气候记录阵列中的一处重大空白。科考团队还使用两台小型钻机钻取了两根浅冰芯，长度分别为116米与103米，覆盖了过去800至1000年的气候演化历史。从钻孔孔内及冰芯内部捕获气泡中提取的古空气样本，可用于解析大气成分随时间的变化规律。
极光盆地钻取点位距离澳大利亚凯西站（Casey station）约550公里。该项目的科学负责人为澳大利亚南极分部的马克·柯伦（Mark Curran）博士。
本冰芯将通过测量多种化学组分，以重建过去的气候历史。极光盆地科考团队将使用Picarro激光光谱仪（Picarro laser spectrometer），对总长400米的冰芯中的水（H₂O）同位素——即氧与氢的不同核素形式——开展现场测定。例如，低温环境下形成的冰中会含有更多¹⁶O，而暖温条件下形成的冰则会富集更重的同位素¹⁸O。这类同位素变化主要受气温调控，科学家可据此反推降雪形成时的当地温度。相较于将样本带回实验室后再开展测量，现场同位素测定可让科考团队在野外作业结束时，直接获取跨度达2000年的温度记录序列。
冰芯样本还会被切割留存，用于后续实验室中甲磺酸（methanesulphonic acid，缩写MSA）的分析。甲磺酸由大气中二甲基硫（dimethylsulphide）氧化生成，而二甲基硫本身由南大洋中的部分浮游植物物种产生。冰芯中的甲磺酸含量与该区域海冰的最大覆盖范围呈正相关：海冰覆盖面积越大，海冰消融后浮游植物的活动就越旺盛，甲磺酸的生成量也就越高。
其中一根120米长的冰芯将专门用于硫同位素分析，以评估火山活动“强迫”（forcing，即对自然气候变率的影响）随时间的变化效应。类似地，科研人员还将测量冰芯中的二氧化碳浓度，以评估温室气体对自然气候变率的强迫作用；而铍-10（beryllium-10）的测量结果则可反映太阳活动的强迫效应。
来自美国沙漠研究所（Desert Research Institute）的科学家将通过测量400米冰芯中的多种化学物质与元素，构建精细化的气候记录。这些测量对象包括镁、铁等粉尘示踪物，火灾灰烬，钠、溴等海水示踪物，以及铜、镉等火山示踪物。此类分析将有助于确定冰芯的年代序列，并为近代自然气溶胶与污染水平提供关键参考数据。
最后，科考团队将从一根120米冰芯顶部的粒雪冰（firn ice）中提取空气样本。粒雪冰为未固结的冰体，含有大量孔隙；与内部空气被捕获为气泡的固结冰不同，粒雪冰中的空气更新鲜，更接近现代大气，可记录近数十年来的气体浓度变化（包括二氧化碳、一氧化碳、甲烷、氧气与氮气）。这将有助于科学家更好地理解碳循环以及人为活动引发的气候变化。
极光盆地是本次研究的理想点位：该区域年降雪量约合13厘米冰厚，足以提供该大陆该区域过去2000年逐年气候变化的首份连续记录。此外，极光盆地拥有南极大陆部分最厚的冰盖——厚度超过3公里，这类冰层的年龄可能超过100万年。本次2000年冰芯钻取过程中获取的数据，可帮助科学家定位适合钻取百万年古老冰芯的最优点位。