Isotopic constraints on past ozone layer in polar ice (ISOL-ICE)

对极地冰中过去臭氧层的同位素限制（ISOL-ICE）

• 批准号: NE/N011813/1
• 负责人: Markus Frey
• 金额: $ 80.36万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FN011813%2F1
• 关键词: Isotopic; constraints; past; ozone; layer

The ozone layer shields all land-based life forms from harmful ultraviolet radiation; and indirectly influences the climate at the Earth's surface, including temperature and winds, particularly near the poles. Man-made halocarbons, used for example in refrigerators and spray cans, were released to the atmosphere and have caused significant destruction of the ozone layer since the late 1970s, especially above Antarctica during spring-time. Because the use of many halocarbons was banned by the 1989 Montreal Protocol, the ozone layer is expected to recover to the conditions of the 1960s and early 1970s within this century.However, the thickness of the ozone layer is also influenced by natural causes, which are less well understood and which make predictions of future ozone and climate less certain. Natural causes include variations in the sun's activity, volcanic eruptions, release of biogenic halocarbons and atmospheric circulation. Currently there is very little information on the natural variability of the ozone layer over historic time scales, i.e. before direct observations started in the early 20th century. However, understanding the natural variability of the ozone layer and the underlying causes is necessary to evaluate the effectiveness of climate and ozone policy options. It is also necessary in order to improve predictions of ground level UV radiation, which is recognized as an environmental carcinogen and a major concern for human health.One way to go back in time beyond the era of modern measurements is the use of proxies measured in polar ice cores. Apart from a recently proposed biomarker there are no quantitative proxies of past UV radiation. Here we propose to measure the isotopes of nitrogen and oxygen in the nitrate ion in polar ice to reconstruct past ultraviolet radiation and therefore the ozone layer. Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. In the very dry regions of inner Antarctica snow is exposed to sunlight for many months before being buried by snowfall. During that exposure the nitrate in the snow is decomposed by solar UV radiation; during that process the heavier nitrogen isotopes in nitrate are observed to stay preferentially in the snow, whereas the lighter ones escape to the atmosphere above. That fractionation depends on the wavelength and duration of the UV radiation. We hypothesize that once the nitrate in snow is buried at depth, it preserves an isotopic fingerprint of down-welling UV radiation and therefore of the thickness of the ozone layer.We propose to collect a shallow ice core from East Antarctic Plateau, where low accumulation rates prevail, to develop and apply a new ice core proxy based on the stable isotopes of nitrate, to constrain trends in the ozone layer above Antarctica over the last 1kyr. To do this, we will calibrate the ice core signal with observations of the ozone layer above Antarctica since the 1950s, and then extrapolate that relationship to the more distant past.Using numerical models we will investigate the underlying causes of the ice core based reconstruction of past variability in the ozone layer. Particular questions we will attempt to answer include: has stratospheric ozone changed in the past; and how did solar variability, natural emissions of halocarbons, or volcanic eruptions contribute to the reconstructed trends?

臭氧层屏蔽了所有陆基生命形式，免受有害的紫外线辐射。并间接影响地球表面的气候，包括温度和风，尤其是在极点附近。自1970年代后期以来，人为的卤代碳（例如在冰箱和喷雾罐中）被释放到大气中，并造成了臭氧层的严重破坏，尤其是春季期间南极上方的臭氧层。由于1989年蒙特利尔方案禁止使用许多卤代碳，因此预计臭氧层将恢复到本世纪内1960年代和1970年代初的条件。否则，臭氧层层的厚度也受到天然原因的影响，这些臭氧层的厚度也不太理解，并且对未来的臭氧和气候的预测不那么确定。自然原因包括太阳活性的变化，火山喷发，生物盐的释放和大气循环。当前，关于历史时间尺度上臭氧层的自然变异性的信息很少，即在20世纪初期直接观察之前。但是，了解臭氧层和根本原因的自然变异性对于评估气候和臭氧政策选择的有效性是必要的。为了改善地面紫外线辐射的预测，这也是必要的，紫外线辐射被认为是一种环境致癌，并且对人类健康的主要关注。除了最近提出的生物标志物外，没有过去的紫外线辐射的定量代理。在这里，我们建议测量极性冰中硝酸盐离子中氮和氧的同位素，以重建过去的紫外线辐射，从而重建臭氧层。同位素是具有相同数量质子但中子数不同的相同元素的原子。在南极内部雪的非常干燥的地区，在被降雪埋葬之前，雪被暴露于阳光。在这种暴露期间，雪中的硝酸盐被太阳紫外线辐射分解。在此过程中，观察到硝酸盐中较重的氮同位素可以优先地留在雪中，而较轻的氮同位素则逃到上面的大气中。分馏取决于紫外线辐射的波长和持续时间。我们假设一旦将雪的硝酸盐深度埋在深度，它就会保留一个同位素的指纹倾斜的紫外线辐射，因此是臭氧层的厚度。我们提议从东南极高原收集浅层冰核心，在低积累率中，低积累速率占据了新的冰核，并在新的冰核心上施加了稳定的稳定性。在最后1公里上方的南极上方。为此，我们将通过自1950年代以来对南极上方的臭氧层观察到冰芯信号，然后推断这种与较远的过去的关系。使用数值模型，我们将研究臭氧层中过去变异性的基于冰核心重建的根本原因。我们将尝试回答的特定问题包括：过去的平流层臭氧改变；太阳可变性，卤代碳或火山喷发的自然排放如何有助于重建趋势？

项目成果

New insights into the atmospheric oxidising capacity above the Antarctic Plateau

对南极高原上方大气氧化能力的新见解

• 发表时间: 2018
• 作者: Frey M. M.

Chemistry in the Cryosphere - (In 2 Parts)

冰冻圈化学 -（分 2 部分）

• DOI: 10.1142/9789811230134_0017
• 发表时间: 2022
• 作者: Miller L

The TropD software package (v1): standardized methods for calculating tropical-width diagnostics

• DOI: 10.5194/gmd-11-4339-2018
• 发表时间: 2018-10-26
• 期刊: GEOSCIENTIFIC MODEL DEVELOPMENT
• 影响因子: 5.1
• 作者: Adam, Ori;Grise, Kevin M.;Ming, Alison
• 通讯作者: Ming, Alison

Increasing Accumulation of Perfluorocarboxylate Contaminants Revealed in an Antarctic Firn Core (1958-2017).

• DOI: 10.1021/acs.est.2c02592
• 发表时间: 2022-08-16
• 期刊: ENVIRONMENTAL SCIENCE & TECHNOLOGY
• 影响因子: 11.4
• 作者: Garnett, Jack;Halsall, Crispin;Winton, Holly;Joerss, Hanna;Mulvaney, Robert;Ebinghaus, Ralf;Frey, Markus;Jones, Anna;Leeson, Amber;Wynn, Peter
• 通讯作者: Wynn, Peter

Summer variability of the atmospheric NO 2 : NO ratio at Dome C on the East Antarctic Plateau

东南极高原 Dome C 大气 NO 2 : NO 比值的夏季变化

• DOI: 10.5194/acp-22-12025-2022
• 发表时间: 2022
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: Barbero A