First study of the global Nickel and Aluminium Layers in the upper atmosphere (NIALL)

首次研究高层大气中的全球镍和铝层（NIALL）

• 批准号: NE/P001815/1
• 负责人: John Plane
• 金额: $ 80.21万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FP001815%2F1
• 关键词: First; study; global; Nickel; Aluminium

The edge of the Earth's atmosphere is approximately 100 km above the surface, in a region known as the mesosphere/lower thermosphere (MLT). This part of the atmosphere is subject to high energy inputs from above in the form of extreme UV radiation and energetic particle precipitation, and a roughly equal amount of energy from breaking atmospheric gravity waves which propagate up from the lower atmosphere. The MLT also acts as a filter of waves that propagate from the troposphere into the ionosphere, which has important implications for space weather. Furthermore, energetic solar protons and electrons from the radiation belts produce highly reactive species in the MLT, which can then be transported down into the stratosphere, affecting the ozone layer and impacting on tropospheric climate. The MLT is also extremely sensitive to climate change, due to the cooling effect of increasing greenhouse gases such as CO2, ozone depletion in the stratosphere, and changes to the large-scale atmospheric circulation. However, it is a difficult region in which to make direct measurements, because it is more than 40 km higher than altitudes reached by research balloons or aircraft, and is at least 100 km lower than short-lived satellite orbits. Rocket-borne measurements do provide direct access, but are unsuitable for sustained global measurements. Fortunately, the ablation of cosmic dust particles entering the atmosphere from space deposits metal atoms such as Na and Fe in layers around 90 km altitude. These layers can be observed with lasers from the ground (lidar) and by satellite-borne spectrometers, providing detailed information about the chemistry and physics (wind, temperature, gravity waves) of the region. There is increasing evidence that accurate simulations of changes to the Earth's climate require models with a well resolved and accurate stratosphere and mesosphere, and so metal species in the upper atmosphere offer a unique way of observing this region and of testing the accuracy of climate models.The purpose of this proposal is to make the first ever study of Ni and Al chemistry in the MLT. The Ni layer has recently been observed for the first time: it is much broader than the well-studied layers such as Na and Fe, and the concentration of Ni atoms is more than 10 times higher than expected based on its cosmic abundance. These very unexpected features need to be understood, since there is the clear potential to develop lidar observations of the Ni layer as a probe of the entire MLT from 70 to 115 km. Aluminium makes a very interesting contrast with Ni. The Al-O bond is so strong that it is very likely there is a substantial layer of the AlO radical in the MLT. This species has a strong optical absorption in the green part of the visible spectrum, and so there is the exciting prospect of making lidar observations of AlO and developing an accurate temperature probe over the full range of mesospheric temperatures.The project will involve first making a series of experimental studies of key neutral and ion-molecule reaction rates in the gas phase, in order to understand the unique characteristics of the Ni layer and the likely concentration of the AlO layer. At the same time, we will use a novel instrument to simulate the ablation of Ni and Al from micron-sized fragments of meteorites such as Allende and Murchison. From this a model will be developed which predicts the injection rates of these elements into the MLT as a function of location and season. The chemistry of Ni and Al, together with their meteoric ablation rates, will then be placed into a global chemistry-climate model. Of particular interest will be to see how the Ni and AlO layers are predicted to respond to perturbations caused by major solar storms, the 11-year solar cycle, and climate change in the MLT over the past 70 years and projected forward to 2100.

地球大气层的边缘大约在地表以上100公里处，这一区域被称为中间层/低热层(MLT)。大气层的这一部分受到来自上方以极端紫外线辐射和高能粒子降水形式的高能量输入的影响，以及从较低大气向上传播的破碎大气重力波的大致相等的能量。MLT还充当从对流层传播到电离层的波的过滤器，这对空间天气具有重要影响。此外，来自辐射带的高能太阳质子和电子在MLT中产生高活性物质，然后可以向下输送到平流层，影响臭氧层并影响对流层气候。由于二氧化碳等温室气体的增加、平流层臭氧的消耗以及大尺度大气环流的变化，MLT对气候变化也极其敏感。然而，这是一个很难进行直接测量的地区，因为它比研究气球或飞机达到的高度高40多公里，比寿命短的卫星轨道至少低100公里。火箭上的测量确实提供了直接的途径，但不适合持续的全球测量。幸运的是，从太空进入大气层的宇宙尘埃粒子在大约90公里高度的层中沉积了金属原子，如Na和Fe。这些层可以用地面激光(激光雷达)和星载光谱仪观测，提供有关该地区化学和物理(风、温度、重力波)的详细信息。越来越多的证据表明，对地球气候变化的准确模拟需要具有良好分辨率和准确的平流层和中间层的模式，因此高层大气中的金属物种为观察这一区域和测试气候模式的准确性提供了一种独特的方式。这项提议的目的是在MLT中首次研究镍和铝的化学。最近首次观测到了镍层：它比Na和Fe等研究充分的层宽得多，根据其宇宙丰度，镍原子的浓度比预期高出10倍以上。需要了解这些非常意想不到的特征，因为显然有可能发展激光雷达对镍层的观测，作为对整个MLT从70公里到115公里的探测。铝和镍形成了非常有趣的对比。Al-O键很强，很可能在MLT中有一层AlO自由基。该物种在可见光谱的绿色部分有很强的光吸收，因此有可能对AlO进行激光雷达观测，并开发出在整个中间层温度范围内精确的温度探测器。该项目将首先对气相中关键的中性和离子-分子反应速率进行一系列实验研究，以了解Ni层的独特特征和AlO层的可能浓度。同时，我们将使用一种新的仪器来模拟微米级陨石碎片如Allende和Murchison对Ni和Al的烧蚀。由此，将建立一个模型，预测这些元素在MLT中的注入速率随地点和季节的变化。然后，镍和铝的化学成分以及它们的流星烧蚀率将被放入全球化学-气候模型中。尤其令人感兴趣的是，如何预测Ni和AlO层对主要太阳风暴、11年太阳周期以及过去70年和预测到2100年的MLT中的气候变化造成的扰动做出反应。

项目成果

On the relationship between the mesospheric sodium layer and the meteoric input function

中层钠层与大气输入函数的关系

• DOI: 10.5194/angeo-2023-20
• 发表时间: 2023
• 作者: Li Y

The Meteoric Ni Layer in the Upper Atmosphere

高层大气中的流星镍层

• DOI: 10.1029/2020ja028083
• 发表时间: 2020
• 期刊: Space Physics
• 作者: Daly S

Cosmic dust fluxes in the atmospheres of Earth, Mars, and Venus

• DOI: 10.1016/j.icarus.2019.113395
• 发表时间: 2020-01-01
• 期刊: ICARUS
• 影响因子: 3.2
• 作者: Carrillo-Sanchez, Juan Diego;Carlos Gomez-Martin, Juan;Plane, John M. C.
• 通讯作者: Plane, John M. C.

A Comparison of the Midlatitude Nickel and Sodium Layers in the Mesosphere: Observations and Modeling

• DOI: 10.1029/2021ja030170
• 发表时间: 2022-02
• 期刊: Journal of Geophysical Research: Space Physics
• 作者: J. Jiao;W. Feng;Fang Wu;Fuju Wu;Haorang Zheng;Lifang Du;Guotao Yang;J. Plane

Ablation of Ni from micrometeoroids in the upper atmosphere: Experimental and computer simulations and implications for Fe ablation

高层大气中微流星体对镍的烧蚀：实验和计算机模拟以及对铁烧蚀的影响

• DOI: 10.1016/j.pss.2019.104725
• 发表时间: 2019
• 期刊: Planetary and Space Science
• 影响因子: 2.4
• 作者: Bones D