CEDAR Postdoc: The Effect of Atmospheric Tides on the Equatorial and Near-Polar Ionosphere

这个项目研究赤道和近极纬度的中性低层大气和电离层之间的潮汐耦合。最近发现对流层潮汐对赤道电离层的结构有强烈的影响，这一发现激发了这项工作，并为解决潮汐耦合对电离层的影响的目标方法奠定了基础。对来自TIMED（热层电离层中间层能量学和动力学）和IMAGE（磁层-极光全球探测成像仪）卫星最近的紫外线（UV）夜光观测的分析表明，夜间电离层的纬向结构与大气潮汐之间存在相关性。耦合机制是中性大气潮汐与e区发电机的相互作用，通过f区高度的等离子体抬升对纬向结构进行耦合。这个项目将结合实验数据和模拟来研究潮汐对电离层的影响的全球性质，从它们的明显起源到热层。气象、电离层和气候星座观测系统和台湾的福尔摩沙卫星任务#3 （COSMIC/FORMOSAT-3）任务每天提供超过1500个GPS（全球定位系统）的电子密度剖面，以及从近地表到60公里高度的温度、压力和折射率剖面，具有相当的地理和时间分辨率。这些剖面具有很高的精度，因此影响电离层的潮汐结构在电离层高度应该是很明显的；此外，在平流层和对流层中也可以探测到与对流层强迫相一致的潮汐特征。GPS无线电掩星剖面，包括电子密度、温度、压力和折射率，是比较电离层和潮汐研究的一个很好的资源，使用非相干散射雷达（ISR）测量电子密度、离子漂移速度和温度，以及衍生的中性风。来自Poker Flat、Millstone Hill和Jicamarca的ISR测量结果将用于检查赤道、中纬度和高纬度地区的潮汐效应，这些地区具有较高的时间和局部空间覆盖率。潮汐结构随海拔、纬度和季节的变化将与TIME-GCM/GSWM（热层电离层-中间层电动力学环流模式/全球尺度波浪模式）的模拟结果进行比较。

This project investigates tidal coupling between the neutral lower atmosphere and the ionosphere at equatorial and near-polar latitudes. The recent discovery that tropospheric tides have a strong effect on the structure of the equatorial ionosphere at altitudes extending up through the F-region motivates this work, and was the basis for the targeted approach to addressing the effects of tidal coupling on the ionosphere that will be undertaken. Analysis of recent ultraviolet (UV) nightglow observations from the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) and IMAGE (Imager for Magnetosphere-to-Aurora Global Exploration) satellites demonstrated that there is a correlation between zonal structures seen in the nighttime ionosphere with the atmospheric tides. The coupling mechanism was interaction of tides in the neutral atmosphere with the E-region dynamo, which couples the zonal structure via plasma uplift through F-region altitudes. This project will use a combination of experimental data and simulations to investigate the global nature of tidal effects on the ionosphere, from their apparent origins through the thermosphere. The Constellation Observing System for Meteorology, Ionosphere and Climate and Taiwan's Formosa Satellite Mission #3 (COSMIC/FORMOSAT-3) mission provides over 1500 GPS (Global Positioning System's) radio occultation profiles of electron density from 100 to 450 km altitude every day, as well as profiles of temperature, pressure, and refractivity from near the surface to 60 km altitude with substantial geographic and temporal resolution. The profiles have tight accuracies such that the tidal structures that affect the ionosphere should be clearly evident at ionospheric altitudes; in addition, tidal features consistent with tropospheric forcing may also be detectable in the stratosphere and troposphere. The GPS radio occultation profiles, of electron density, temperature, pressure, and refractivity, are a good resource for comparison with ionospheric and tidal studies using incoherent scatter radar (ISR) measurements of electron density, ion drift velocities and temperatures, and derived neutral winds. ISR measurements from Poker Flat, Millstone Hill, and Jicamarca will be used to allow examination of tidal effects at equatorial, mid, and high northern latitudes with high temporal and local spatial coverage. The observations of tidal structure with altitude, latitude, and season will be compared with simulations from the TIME-GCM/GSWM (Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model/Global Scale Wave Model).