Chemistry and Physics Faculty Articles
Equatorial F region neutral winds and shears near sunset measured with chemical release techniques
ORCID
0000-0003-2435-9416
Document Type
Article
Publication Title
Journal of Geophysical Research: Space Physics
ISSN
2169-9402
Publication Date
9-7-2015
Keywords
sunset electrodynamics, sounding rocket, F region neutral winds, equatorial ionosphere
Abstract
The period near sunset is a dynamic and critical time for the daily development of the equatorial nighttime ionosphere and the instabilities that occur there. It is during these hours that the preconditions necessary for the later development of Equatorial Spread F (ESF) plasma instabilities occur. The neutral dynamics of the sunset ionosphere are also of critical importance to the generation of currents and electric fields; however, the behavior of the neutrals is experimentally understood primarily through very limited single-altitude measurements or measurements that provide weighted altitude means of the winds as a function of time. To date, there have been very few vertically resolved neutral wind measurements in the F region at sunset. We present two sets of sounding rocket chemical release measurements, one from a launch in the Marshall Islands on Kwajalein atoll and one from Alcantara, Brazil. Analysis of the release motions has yielded vertically resolved neutral wind profiles that show both the mean horizontal winds and the vertical shears in the winds. In both experiments, we observe significant vertical gradients in the zonal wind that are unexpected by classical assumptions about the behavior of the neutral wind at these altitudes at sunset near the geomagnetic equator.
DOI
10.1002/2015JA021462
Volume
120
Issue
10
First Page
9004
Last Page
9013
Additional Comments
©2015. American Geophysical Union. All Rights Reserved.
NSUWorks Citation
Kiene, A., Larsen, M. F., & Kudeki, E. (2015). Equatorial F region neutral winds and shears near sunset measured with chemical release techniques. Journal of Geophysical Research: Space Physics, 120, (10), 9004 - 9013. https://doi.org/10.1002/2015JA021462. Retrieved from https://nsuworks.nova.edu/cnso_chemphys_facarticles/291
Comments
The work at Clemson was partially supported by NASA grant NNX13AF29G and by NSF grant AGS-1007539. Data used in this study are available from the authors upon request (akiene@clemson.edu). Support for the work at the University of Illinois came from NASA grant NNX10AL94G.
Alan Rodger thanks two anonymous reviewers for their assistance in evaluating this paper.