Collaborative Research: CEDAR--Assimilative Analysis of Low- and Mid-latitude Ionospheric Electrodynamics

地球赤道电离层相对于中性风和温度以及等离子体密度和离子/电子温度等基本参数的垂直分布的现象是复杂的。 复杂性的根本原因在于热层风、电导率、电场和电流在地磁场影响下相互耦合的动力学。 这一区域还暴露在不断变化的地面天气和空间天气条件下，这些条件加在一起造成了巨大的日常变化。 该项目的目标是制定专门针对低纬度电动力学问题的综合数据同化方法，以缩小我们对纵向依赖性的起源及其日常变化的理解方面的差距。 该项目将扩大教育和培训经验的一名研究生在得克萨斯州达拉斯大学（UTD）和博士后研究员在科罗拉多博尔德大学（CU-Boulder）通过他们参与这种多方面的研究方法。 UTD的研究生将花一个夏天访问CU-Boulder和NCAR的培训使用数值建模和数据同化工具。 该研究与现代社会对更强大和可靠的通信、导航和定位系统的需求高度相关。本项目要解决的具体科学问题包括：（1）对观测到的白天大尺度赤道现象的逐日变化沿着纵向和季节依赖性的原因进行定量分析;以及2）地磁场的几何形状和大小在多大程度上控制纵向依赖性，以及来自地球表面纵向不对称源的大气潮汐。

The phenomenology of the Earth's equatorial ionosphere with respect to vertical profiles of basic parameters such as the neutral wind and temperature as well as plasma density and ion/electron temperatures is complex. The root causes of the complexity lie in the mutually coupled dynamics of thermospheric winds, conductivity, electric fields and currents operating under the influence of the geomagnetic field. This region is also exposed to the continual varying conditions of both terrestrial weather and space weather, which taken together give rise to large day-to-day variability. The project's objective is to achieve the development of a comprehensive data assimilation approach tailored specifically to the problem of low-latitude electrodynamics that would close the gap in our understanding of the origins of longitudinal dependence and its day-to-day variability. The project would broaden the education and training experiences of a graduate student at University of Texas Dallas (UTD) and a postdoctoral researcher at University of Colorado Boulder (CU-Boulder) by their participation in this multi-faceted research approach. The UTD graduate student will spend a summer visiting CU-Boulder and NCAR for training in the use of numerical modeling and data assimilation tools. The investigation is highly relevant to the need of the modern society for more powerful and reliable communication, navigation and positioning systems. Specific science questions to be addressed in this project include 1) the quantitative breakdown of the causes of the observed day-to-day variability of daytime large scale equatorial phenomena along with its longitudinal and seasonal dependency; and 2) to what extent is the longitudinal dependence controlled by the geometry and magnitude of geomagnetic fields, and by the atmospheric tides originating from longitudinal asymmetric sources on the Earth's surface.