US-Nigeria Cooperative Research: Improvements of the International Reference Ionosphere at Low Latitudes

0002144Bilitza该奖项支持Dieter Bilitza博士与位于马里兰州格林贝尔特戈达德太空飞行中心的雷神技术服务公司之间的一项为期三年的合作研究项目；尼日利亚伊洛林大学物理系教授Jacob Olusegun Adeniyi；以及科特迪瓦科迪大学大气物理实验室的Olivier Obrou教授。电离层是大气层中介于中间层和散逸层之间的那部分。它的层被太阳紫外线辐射电离，这有利于某些无线电波在地球上的长距离传输。对于任何利用电离层无线电波传输信号的地面或空间遥感技术来说，充分了解电离层电子密度是必不可少的。用于确定这些密度的最广泛使用的模型，国际参考电离层（IRI），缺乏对最大电子密度发生的低纬度地区的描述，这限制了它提供导航和通信系统所需的修正的能力。这三名研究人员将分析由位于布基纳法索、尼日利亚和科特迪瓦磁赤道附近的四个地面探测器收集的电离层底部电子密度剖面的赤道观测结果。研究结果将用于改进IRI模型中电子密度的规格。这一信息补充了美国、印度和太平洋地区现有的测量数据，并完成了磁赤道附近地面探测仪纵向链电子密度数据的收集。这些数据集还将使研究人员能够对非洲地区赤道电离层的变化进行定量描述。该项目结合了在四个站点进行的人工离子图缩放和现代离子图还原技术。通过这个项目，主要研究人员希望更好地了解形成赤道电离层的过程，这将导致IRI标准模型的改进。一个包括非洲测量的更新的IRI模型将使未来的研究人员受益，而且它还将广泛应用于高频和地对星通信系统。此外，预期的结果将扩展有关电离层物理的知识。国际项目司和大气科学司共同为这个项目提供资金。

0002144BilitzaThis award supports a three-year collaborative research project among Dr. Dieter Bilitza, with the Raytheon Technical Services Company at Goddard Space Flight Center in Greenbelt, MD; Professor Jacob Olusegun Adeniyi, of the Department of Physics at the University of Ilorin in Nigeria; and Professor Olivier Obrou, at the Laboratoire de Physique de l'Atmosphere at the University of Cocody in the Ivory Coast. The ionosphere is that part of the atmosphere which lies between the mesophere and the exosphere. Its layers are ionized by solar ultraviolet radiation, which facilitates the transmission of certain radio waves over long distances on earth. A good knowledge of ionospheric electron density is essential for any ground or space remote sensing technique that uses the ionospheric radio waves for the transmission of its signals. The most widely used model for determining these densities, the International Reference Ionosphere (IRI), lacks a description of the low latitude regions where the largest electron densities occur, which limits its ability to provide the corrections needed by navigation and communications systems. The three investigators will analyze equatorial observations of the bottom-side ionospheric electron density profiles collected by four ground-based sounders located near the magnetic equator in Burkina Faso, Nigeria, and the Ivory Coast. The results will be used to improve the specification of electron density in the IRI model. This information complements existing measurements in the American, Indian, and Pacific sectors, and completes the collection of electron density data from the longitudinal chain of ground-based sounders near the magnetic equator. These data sets will also enable the researchers to develop a quantitative description of the variability of the equatorial ionosphere in the African sector. This project combines the manual ionogram scaling done at the four stations with modern ionogram reduction techniques. Through this project the principal investigators expect to achieve a better understanding of the processes that shape the equatorial ionosphere, which will lead to improvements in the IRI standard model. An updated IRI model, which includes African measurements, will benefit future researchers, and it will also have broad application in high frequency and ground-to-satellite communications systems. Additionally, the anticipated results should expand the knowledge about ionospheric physics.The Division of International Programs and the Division of Atmospheric Sciences are jointly providing funding for this project.