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NOx and HOx production by energetic electrons and impacts on polar stratospheric ozone (NOHO)

高能电子产生 NOx 和 HOx 及其对极地平流层臭氧 (NOHO) 的影响

基本信息

批准号：
NE/J022187/1
负责人：
David Newnham
金额：
$ 40.26万
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：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ022187%2F1
关键词：
NOx HOx production energetic electrons

项目摘要

Predicting future climate change is intimately linked to understanding what is happening to the climate system in the present, and in the recent past. Studies in the Polar Regions provide vital clues in our understanding of global climate, and early indications of changes arising from the coupling of natural processes, such as variability in the amount of energy from the Sun reaching the Earth, and man-made factors. For example, the polar winter provides the extreme cold, dark conditions in the atmosphere which, combined with chemicals released from man-made chlorofluorocarbon (CFC) gases, has led to destruction of the stratospheric ozone layer 18-25 km above the ground every spring-time since the 1980's. The Southern hemisphere ozone 'hole' is now linked to observed changes in surface temperature and sea-ice across Antarctica, decreased uptake of carbon dioxide by the Southern Ocean, and perturbations to the atmospheric circulation that can affect weather patterns as far away as the Northern hemisphere.Recovery of the ozone layer is expected now that CFC's are banned by international protocols, but this may be delayed by other greenhouse gases we are releasing into the atmosphere and natural processes including changes in the Sun's output. Although the total amount of energy as sunlight changes by a small amount (~0.1%) over the typical 11-year solar cycle, the energetic electrons and protons streaming from the Sun changes dramatically on timescales from hours to years. These particles are guided by the Earth's magnetic field and can enter the upper atmosphere, most intensely over the Polar Regions. A visible effect is the aurora, but the particles can also significantly modify the chemistry of the atmosphere down to the stratospheric ozone layer. Powerful solar storms can also damage satellites and disrupt electrical power networks. However the mechanisms by which energetic electrons generated by the Sun enter the Earth's atmosphere, and the complex, interacting processes that affect stratospheric ozone are not well understood, which limits our ability to accurately predict future ozone changes and impacts on climate.We propose answering major unresolved questions about the impact of energetic electrons on stratospheric ozone by making observations of the middle atmosphere from Halley station in Antarctica. This location is directly under the main region where energetic electrons enter the atmosphere, making it ideal to observe the resulting effects. We will install a state-of-the-art microwave radiometer there alongside other equipment run by BAS scientists. By analysing the microwaves naturally emitted by the atmosphere high above us we can work out how much ozone there is 30-90 km above the ground as well as measuring chemicals produced in the atmosphere by energetic electrons that affect ozone. We will make observations throughout two complete Antarctic years/winters (1/2013-2/2015) and interpret them with the help of data from spacecraft that orbit the Earth and measure the energetic electrons entering the atmosphere. We will use the Antarctic observations and develop computer-based models to better understand the impact of energetic electrons on the atmosphere. The ultimate goal is to further understanding of the processes that lead to climate variability in the Polar Regions and globally - highly relevant for UK environmental science and collaborative research at an international level in which BAS and Leeds play a key role.

预测未来的气候变化与了解现在和最近过去气候系统正在发生的事情密切相关。极地区域的研究为我们理解全球气候提供了重要线索，并提供了自然过程耦合引起的变化的早期迹象，例如太阳到达地球的能量的变化量以及人为因素。例如，极地冬季提供了大气中极端寒冷、黑暗的条件，再加上人造氯氟化碳气体释放出的化学物质，导致了自1980年S以来每年春季地面上空18-25公里处的平流层臭氧层被破坏。南半球臭氧“空洞”现在与观察到的南极洲表面温度和海冰的变化、南大洋对二氧化碳吸收的减少以及对大气循环的扰动有关，这些扰动可能会影响远至北半球的天气模式。由于国际协议禁止使用氯氟化碳，臭氧层有望恢复。但这可能会被我们正在释放到大气中的其他温室气体和自然过程推迟，包括太阳产量的变化。虽然太阳光的总能量在典型的11年太阳周期中变化很小(~0.1%)，但从太阳流出的高能电子和质子在几小时到几年的时间尺度上变化很大。这些粒子由地球磁场引导，可以进入高层大气，最强烈的是在极地地区。一种可见的效果是极光，但这些粒子也可以显著改变大气的化学成分，一直到平流层臭氧层。强烈的太阳风暴也会损坏卫星，扰乱电力网络。然而，太阳产生的高能电子进入地球大气层的机制，以及影响平流层臭氧的复杂、相互作用的过程尚不清楚，这限制了我们准确预测未来臭氧变化和对气候影响的能力。我们建议通过在南极洲哈雷站观测中间大气来回答高能电子对平流层臭氧影响的主要悬而未决的问题。这个位置就在高能电子进入大气层的主要区域的正下方，这使它成为观察由此产生的效应的理想地点。我们将在那里安装一台最先进的微波辐射计，以及BAS科学家运行的其他设备。通过分析我们头顶上空大气自然发出的微波，我们可以计算出离地面30-90公里处有多少臭氧，以及测量大气中影响臭氧的高能电子产生的化学物质。我们将在南极两个完整的年份/冬季(1/2013-2/2015)进行观测，并借助绕地球运行的航天器提供的数据进行解释，并测量进入大气层的高能电子。我们将利用南极观测并开发基于计算机的模型，以更好地了解高能电子对大气的影响。最终目标是进一步了解导致极地地区和全球气候变化的过程，这与英国环境科学和国际合作研究高度相关，BAS和利兹在其中发挥关键作用。