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Thermospheric Heating Modes and their Effects on Satellites

热层加热模式及其对卫星的影响

基本信息

批准号：
NE/N01099X/1
负责人：
Mervyn Freeman
金额：
$ 41.1万
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%2FN01099X%2F1
关键词：
Thermospheric Heating Modes their Effects

项目摘要

The thermosphere is the uppermost layer of our atmosphere at the edge of space (85 to 1000 km altitude). Within this region orbit thousands of satellites worth billions of pounds that provide essential modern services including satnav, satcomms, and remote sensing. There are also many thousands more orbiting pieces of man-made space debris which present a significant risk to operational satellites because of the chance of collision.We have now passed a tipping point where the increase in debris from collisions exceeds losses, leading to a net growth of the space debris population and thus ever-increasing risk of collisions.Short- and long-term predictions of satellite and debris trajectories are vital to avoid the destruction of satellites in low-Earth orbit. A major factor limiting factor is knowing the density of the thermosphere, which can vary by up to 800% during extreme times. The variability is due to effects in near-Earth space from disturbances on the Sun, collectively called space weather.In the polar regions, where there is the greatest concentration of satellites, the largest uncertainties in thermospheric density arise from "Joule" heating. This is caused by collisions between electrically-charged and neutral particles in the thermosphere, driven by space weather. Crucially, we have yet to properly understand when and where Joule heating will occur and how predictable it is. Accurate models and prediction of Joule heating are vital to safeguard the space assets on which modern society depends.In this project we will develop a better understanding of Joule heating by analysing more than a decade of data from two major international polar instrument networks. We will use a statistical method developed in meteorology called Empirical Orthogonal Function (EOF) analysis, which is capable of uncovering the underlying patterns in a large, noisy data set. In this way we will both resolve the Joule heating in unprecedented detail and separate it into patterns which depend to greater or lesser degrees on the solar sources of space weather. Since these sources can be observed before they cause space weather at Earth, this will allow us to quantify the limits of predictability of the Joule heating. By then assessing the relationship between the Joule heating and satellite trajectories, this will allow us to describe which orbital paths are most at risk from space weather.

热层是我们大气层的最上层，位于太空边缘（海拔85至1000公里）。在这个区域内，有价值数十亿英镑的数千颗卫星在轨道上运行，提供包括卫星导航、卫星通信和遥感在内的基本现代服务。还有成千上万的人造空间碎片在轨道上运行，它们有可能发生碰撞，对正在运行的卫星构成重大威胁。我们现在已经越过了一个临界点，碰撞碎片的增加超过了损失，导致空间碎片数量的净增长，从而使碰撞的危险不断增加。卫星和碎片轨迹的短期和长期预测对于避免近地轨道卫星的破坏至关重要。一个主要的限制因素是了解热层的密度，在极端时期，热层的密度变化可达800%。这种变化是由于太阳扰动对近地空间的影响，统称为空间天气。在卫星最集中的极地地区，热层密度的最大不确定性来自“焦耳”加热。这是由空间天气驱动的热层中带电粒子和中性粒子之间的碰撞造成的。至关重要的是，我们还没有正确地理解焦耳加热将在何时何地发生，以及它的可预测性如何。焦耳加热的精确模型和预测对于保护现代社会所依赖的空间资产至关重要。在这个项目中，我们将通过分析来自两个主要国际极地仪器网络的十多年数据来更好地理解焦耳加热。我们将使用气象学中开发的统计方法，称为经验正交函数（EOF）分析，该方法能够揭示大型嘈杂数据集中的潜在模式。这样，我们既可以以前所未有的细节解决焦耳加热问题，又可以将其分成不同的模式，这些模式或多或少地取决于空间天气的太阳来源。由于这些源可以在它们引起地球上的空间天气之前被观测到，这将使我们能够量化焦耳加热的可预测性的限制。通过评估焦耳加热和卫星轨迹之间的关系，这将使我们能够描述哪些轨道路径最容易受到空间天气的影响。