Carbonyl sulfide measurements in the GISP2D ice core from Summit, Greenland

极地冰芯包含了古代空气的档案，可以用来重建大气气体成分的历史。该项目涉及分析在格陵兰萨米特钻取的GISP 2D冰芯样品，并将研究硫化羰的大气历史。大气中COS的变化可能与陆地上植物的生长有关，因为它们在光合作用过程中从大气中吸收COS。该项目的COS格陵兰冰芯记录将用于记录过去1000年来陆地植物生长的可能变化，并限制平流层硫酸盐气溶胶层的自然控制。该项目将支持在加州大学欧文分校的博士生的培训，并提供实践研究经验，为几个本科生在国家的最先进的分析化学实验室。它还将通过清洁教育计划支持加州大学欧文分校冰芯实验室在当地初中和高中的K-12推广活动，该计划是由加州大学欧文分校研究生创立和运营的非营利组织。研究人员以前测量了来自几个不同南极地点的冰芯中的COS，恢复了南半球大气的COS记录，时间从几个世纪到几千年不等。作为该项目的一部分，他们将测量来自GISP 2D冰芯的140个样本，并创建过去3000年来北方大气的第一个冰芯COS记录。冰芯空气将被干提取，并与现有的气相色谱-质谱（GC-MS）系统进行分析。COS在大气中的寿命只有2年，其大气收支情况知之甚少。陆地植物通过光合作用从大气中清除COS的估计量远远超过已知的排放量，可能指向一个未确定的自然来源。模拟工作表明，了解工业化前大气中的两极COS差异将对未识别源的性质和大小提供强有力的约束。GISP 2D测量在过去1000年之前，将在高分辨率下进行。这包括小冰期时期，在此期间，南极冰芯记录显示大气COS下降。新的格陵兰测量结果将构成与现有南极记录相似的北方半球。结果将用于研究气候驱动的变化，在大气中的COS和植物生长的变化和变化的影响背景平流层硫酸盐在工业化前的大气。该项目包括利用6箱大气模型进行全面建模工作的计划，该模型将与海洋和陆地植被模型相结合。从3000年到1000年之前的测量将在较低的分辨率下进行，主要目标是进一步了解冰芯中COS的缓慢原位水解损失，这是以前在南极冰芯中观察到的。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值进行评估，被认为值得支持和更广泛的影响审查标准。

Polar ice cores contain an archive of ancient air that can be used to reconstruct history of atmospheric gas composition. This project involves analysis of samples from the GISP2D ice core drilled at Summit, Greenland, and will develop an atmospheric history of carbonyl sulfide (COS). Variations in atmospheric COS can be linked to growth of plants on land because they take up COS from the atmosphere during photosynthesis. The Greenland ice core record of COS from this project will be used to document possible changes in terrestrial plant growth over the last 1000 years and to constrain the natural controls on stratospheric sulfate aerosol layer. This project will support training of a doctoral student at UC Irvine and provide hands-on research experience for several undergraduate students in a state-of-the-art analytical chemistry laboratory. It will also support K-12 outreach activities by the UC Irvine ice core laboratory in local middle and high schools through the CLEAN Education initiative, a non-profit founded and operated by graduate students at UC Irvine.The investigators previously measured COS in ice cores from several different Antarctic sites, recovering COS records of the southern hemisphere atmosphere over periods that range from centuries to multi-millennia. As part of this project, they will measure 140 samples from the GISP2D ice core and create the first ice core COS record of the northern hemisphere atmosphere spanning the last 3000 years. Ice core air will be dry-extracted and analyzed with an existing gas chromatography-mass spectrometry (GC-MS) system. COS lifetime in the atmosphere is only 2 years and its atmospheric budget is poorly understood. Estimates of COS removal from the atmosphere via photosynthesis by land plants far exceed the known emissions, possibly pointing to an unidentified natural source. Modeling work suggests knowing the pole-to-pole COS difference in the preindustrial atmosphere would provide a robust constraint on the nature and magnitude of the unidentified source(s). The GISP2D measurements for the last 1000 years before present will be conducted at high-resolution. This includes the Little Ice Age period, during which Antarctic ice core records display a decline in atmospheric COS. The new Greenland measurements will constitute a northern hemisphere analogue to existing Antarctic records. Results will be used to study climate driven variability in atmospheric COS and implications for changes in plant growth and variability in background stratospheric sulfate in the preindustrial atmosphere. The project includes plans for a comprehensive modelling effort with a 6-box model of the atmosphere, which will be coupled to ocean and terrestrial vegetation models. Measurements from 3000 to 1000 years before present will be conducted at lower resolution and the primary goal will be to gain further insight into the slow in-situ hydrolysis loss of COS in ice cores that has been previously observed in Antarctic ice cores over multi-millennial time scales.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.