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

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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.