[IGPP Everyone] Reminder - Today - Friday April 19, 2019 - Space Physics Seminar - Spring Quarter

[Marjorie Sowmendran]

Reminder – Today - Friday April 19, 2019 


SPACE PHYSICS SEMINAR 

DEPARTMENT OF EARTH, PLANETARY, AND SPACE SCIENCES 

DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES 

UNIVERSITY OF CALIFORNIA, LOS ANGELES 

(AOS M275C, EPSS M288C) 





Longitudinal and Seasonal Variability of Ionospheric Disturbances 



Endawoke Yizengaw 

Space Science Department, The Aerospace Corporation 



Abstract: 

Understanding the physics behind ionospheric disturbances, which are initiated mainly by two major coupling processes, namely: thermosphere-ionosphere coupling (forcing from below) and magnetosphere-ionosphere coupling (forcing from above), become the top-priority of the U. S. National Space Weather Program. Over the past decades' significant progress has been done to understand the origin and mechanisms of ionospheric disturbances. However, characterization of the global ionospheric disturbance as a function of local time, longitude, geomagnetic conditions, and season is still a challenge for the modeling community. Recent advances in networks of distributed ground instruments provide new evidence of longitudinal variations in the mid- and low-latitude ionospheric disturbances/irregularities on a large variety of spatial and temporal scales. Ionospheric irregularity is stronger and has a more prominent impact at low-latitudes where geomagnetic field is nearly horizontal. However, during an intense magnetic storm, ionospheric disturbances may not be restricted to the low-latitude region but can occur at mid-latitudes due to the sharp density gradient at the edge of storm enhanced densities (SEDs) plumes. In this colloquium presentation, the combined diagnostic observations of everything, but the kitchen sink, will be portrayed to demonstrate that forcing from lower thermosphere, like the localized tropospheric gravity waves (GWs) seeding, may be responsible for the formation of the strong longitudinal dependence of ionospheric disturbance/irregularity distribution. Furthermore, potential future research contributions using data from the upcoming ICON, GOLD, and GDC missions will be presented. Finally, results from the successful international scientific team leadership and from participation at the international outreach programs that are designed to expand space science education and instruments (UCLA also involved through AMBER project) into the developing nations will also be discussed. 





Friday, April 19, 2019 

Room 6704 Geology 

3:30 - 5:00 PM 

In-Charge: C. T. Russell 

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