Incoherent Scatter Radar Studies of Hot Oxygen

热氧的非相干散射雷达研究

• 批准号: 0327625
• 负责人: William Oliver
• 金额: --
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-11-15 至 2009-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0327625&HistoricalAwards=false
• 关键词: Incoherent; Scatter; Radar; Studies; Hot

This is a project to study hot oxygen in the upper atmosphere. The energy of solar photons absorbed in the upper atmosphere far exceeds the thermal energy of atmospheric particles (tenth of an eV). Thus, the atmosphere is immersed in a dilute sea of very energetic particles created by solar photon absorption. A prominent member of this collection of energetic particles is hot oxygen, a population of oxygen atoms found to be at a temperature of about 4000 K. This project studies hot O in two ways. First, the incoherent scatter radar (ISR) Data Base at the National Center for Atmospheric Research will be inspected for evidence of the heating effects of hot O. Ions in the topside ionosphere are hotter than classical theory says they should be, and hot O may possibly act as the missing heat source. The hot O density may be deduced from the temperature deficit between classical theory and measurement. The estimates of hot O will be developed into a model and of its behavior. Once the hot O model is established, it may be used to correct previous estimates of cold oxygen concentrations. Though this work explicitly concerns hot O determination and modeling, the longer term aim is to use the 30-year ISR data base to track cold O density throughout that period. If cold O changes from one 11-year solar cycle to the next it may indicate a measurable trend related to global change caused by changes in greenhouse gases or ozone at lower altitudes, changes which are expected to be amplified in atmospheric density at high altitudes. The second method is based on concentrations of hot oxygen ions. If there is neutral hot O, there must be hot oxygen ions present too. The ionosphere will be numerically simulated to determine what densities of hot O ions may be expected to exist in the ionosphere, given the model described above that will be developed for neutral hot O. Since helium ions at 1000 K and hot O at 4000 K have the same temperature-to-mass ratio, they cannot be distinguished by doppler radar techniques. The hot O simulation results will be compared with reported observations of helium ions in the topside ionosphere for likeness to determine if hot oxygen may have masquerading as helium in past published reports. The intellectual merit of the proposed project lies in the fact that it studies a little-known atmospheric species whose presence is expected, or has the potential, to explain a number of discrepancies between theory and observation, e.g., excess satellite drag, airglow, and ionospheric heating at high altitudes, and why satellite and radar measurements of oxygen density differ. The broader impacts of the project lie in several areas, in the integration of classroom and research activity, in the training of graduate and undergraduate students in the scientific process and presentation skills, in the involvement of under-represented groups, and in the provision to the scientific community a model of the behavior of hot O which should be useful in a variety of applications in which thermospheric and/or ionospheric mass or energy budget considerations are important.

这是一个研究高层大气中热氧的项目。在高层大气中吸收的太阳光子的能量远远超过大气粒子的热能（十分之一eV）。因此，大气层沉浸在由太阳光子吸收产生的高能粒子的稀释海洋中。在这些高能粒子中，一个突出的成员是热氧，这是一群温度约为4000 K的氧原子。这个项目以两种方式研究热O。首先，将检查国家大气研究中心的非相干散射雷达（ISR）数据库，以寻找热O加热效应的证据。电离层顶部的离子比经典理论认为的要热，而热的O可能是缺少的热源。热氧密度可以从经典理论和测量之间的温度差推导出来。热O的估计将发展成一个模型和它的行为。一旦热氧模型建立，它可用于校正先前对冷氧浓度的估计。虽然这项工作明确涉及热O的测定和建模，但长期目标是使用30年ISR数据库来跟踪整个期间的冷O密度。如果冷O从一个11年的太阳周期到下一个太阳周期发生变化，它可能表明与低海拔温室气体或臭氧变化引起的全球变化有关的可测量趋势，这些变化预计将在高海拔大气密度中放大。第二种方法是基于热氧离子的浓度。如果有中性的热氧，那么一定也有热氧离子存在。将对电离层进行数值模拟，以确定电离层中可能存在的热氧离子密度，给出上述将为中性热氧离子开发的模型。由于氦离子在1000 K和热O在4000 K有相同的温度质量比，他们不能区分多普勒雷达技术。热氧模拟结果将与报告的观测结果进行比较，以确定热氧是否可能在过去发表的报告中伪装成氦。拟议项目的智力价值在于，它研究了一种鲜为人知的大气物种，其存在预计或有可能解释理论与观测之间的一些差异，例如，过量的卫星阻力，气辉和高海拔电离层加热，以及为什么卫星和雷达测量的氧气密度不同。该项目的更广泛影响体现在几个领域，包括课堂教学与研究活动的结合，对研究生和本科生进行科学过程和演讲技能的培训，让代表性不足的群体参与，并向科学界提供了一个热O行为的模型，该模型在热层和/或热层的各种应用中应该是有用的。或电离层质量或能量预算的考虑是重要的。