|
|
 |
|
|
Ann. Geophys., 25, 701-709, 2007
www.ann-geophys.net/25/701/2007/
© European Geosciences Union 2007
Analysis of equatorial plasma bubble zonal drift velocities in the Pacific sector by imaging techniques
D. Yao and J. J. Makela
Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
Abstract. Using 1024 nights of data from 2002–2005 taken by the Cornell Narrow Field
Imager (CNFI), we examine equatorial plasma bubble (EPB) zonal drift
velocity characteristics. CNFI is located at the Maui Space Surveillance
Site on the Haleakala Volcano (geographic: 20.71° N, 203.83° E;
geomagnetic: 21.03° N, 271.84° E) on the island of Maui, Hawaii. The
imager is set up to view in a magnetic field-aligned geometry in order to
maximize its resolution. We calculate the zonal drift velocities using two
methods: a correlation routine and an EPB west-wall intensity gradient
tracking routine. These two methods yield sizeable differences in the
evenings, suggesting strong pre-local midnight EPB development. An analysis
of the drift velocities is also performed based on the three influencing
factors of season, geomagnetic activity, and solar activity. In general, our
data match published trends and drift characteristics from past studies.
However, we find that the drift magnitudes are much lower than results from
other imagers at similar latitude sectors but at different longitude
sectors, suggesting that zonal drift velocities have a longitudinal
dependence.
Full Article in PDF (393 KB) |
|
|
