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Title: Postsunset rise of F layer height in the equatorial region and its relation to the F layer dynamo polarization fields

Abstract

The ionosonde data are studied for equatorial station, Thumba, to delineate various features of the evening height rise of F layer. Sharp increase of h'F and h{sub p}F2 is observed in the postsunset period for high solar activity. Seasonal variation is observed in this increase of h'F and it is maximum for equinox months. For summer months, there is a delay of about an hour in the time of occurrence of h'F (peak) as compared to winter and equinox months. This delay is shown to be associated with the delay in sunset times in the conjugate E regions. As for magnetic activity dependence, it is found that this height increase is less pronounced for disturbed days for winter and equinox whereas for summer it is marginally higher over the quiet day values. Further, it is observed that the value of h'F (peak) during disturbed periods is almost at the same value of 350 km for all the three seasons. Thus the seasonal variation of magnetic activity effects appears to be mainly governed by the average seasonal variation for quiet times. The increase in F layer height is due to zonal eastward electric fields developed after sunset which is believed tomore » be due to F region dynamo fields. While the main driving force for these fields is the zonal neutral winds, the development of these fields depend on the ratio of the F region to E region conductivity and the longitudinal gradient in the E region conductivity. Experimental observations of both the neutral winds and ionospheric conductivities are examined for their variation with solar activity, season and magnetic activity as both these factors will contribute for the various observed features of the height rise.« less

Authors:
; ;  [1]
  1. National Physical Lab., New Delhi (India)
Publication Date:
OSTI Identifier:
5028664
Resource Type:
Journal Article
Journal Name:
Journal of Geophysical Research; (United States)
Additional Journal Information:
Journal Volume: 95:A5; Journal ID: ISSN 0148-0227
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; F REGION; ELECTRIC FIELDS; VIRTUAL HEIGHT; COMPARATIVE EVALUATIONS; DATA; E REGION; ELECTRIC CONDUCTIVITY; ELECTRON DENSITY; EQUATOR; IONOSONDES; SEASONAL VARIATIONS; SOLAR ACTIVITY; DIMENSIONS; EARTH ATMOSPHERE; ELECTRICAL PROPERTIES; ELECTRONIC EQUIPMENT; EQUIPMENT; EVALUATION; HEIGHT; INFORMATION; IONOSPHERE; PHYSICAL PROPERTIES; PLANETARY IONOSPHERES; RADIO EQUIPMENT; VARIATIONS; 640201* - Atmospheric Physics- Auroral, Ionospheric, & Magetospheric Phenomena

Citation Formats

Goel, M K, Singh, S S, and Rao, B C.N. Postsunset rise of F layer height in the equatorial region and its relation to the F layer dynamo polarization fields. United States: N. p., 1990. Web. doi:10.1029/JA095iA05p06237.
Goel, M K, Singh, S S, & Rao, B C.N. Postsunset rise of F layer height in the equatorial region and its relation to the F layer dynamo polarization fields. United States. doi:10.1029/JA095iA05p06237.
Goel, M K, Singh, S S, and Rao, B C.N. Tue . "Postsunset rise of F layer height in the equatorial region and its relation to the F layer dynamo polarization fields". United States. doi:10.1029/JA095iA05p06237.
@article{osti_5028664,
title = {Postsunset rise of F layer height in the equatorial region and its relation to the F layer dynamo polarization fields},
author = {Goel, M K and Singh, S S and Rao, B C.N.},
abstractNote = {The ionosonde data are studied for equatorial station, Thumba, to delineate various features of the evening height rise of F layer. Sharp increase of h'F and h{sub p}F2 is observed in the postsunset period for high solar activity. Seasonal variation is observed in this increase of h'F and it is maximum for equinox months. For summer months, there is a delay of about an hour in the time of occurrence of h'F (peak) as compared to winter and equinox months. This delay is shown to be associated with the delay in sunset times in the conjugate E regions. As for magnetic activity dependence, it is found that this height increase is less pronounced for disturbed days for winter and equinox whereas for summer it is marginally higher over the quiet day values. Further, it is observed that the value of h'F (peak) during disturbed periods is almost at the same value of 350 km for all the three seasons. Thus the seasonal variation of magnetic activity effects appears to be mainly governed by the average seasonal variation for quiet times. The increase in F layer height is due to zonal eastward electric fields developed after sunset which is believed to be due to F region dynamo fields. While the main driving force for these fields is the zonal neutral winds, the development of these fields depend on the ratio of the F region to E region conductivity and the longitudinal gradient in the E region conductivity. Experimental observations of both the neutral winds and ionospheric conductivities are examined for their variation with solar activity, season and magnetic activity as both these factors will contribute for the various observed features of the height rise.},
doi = {10.1029/JA095iA05p06237},
journal = {Journal of Geophysical Research; (United States)},
issn = {0148-0227},
number = ,
volume = 95:A5,
place = {United States},
year = {1990},
month = {5}
}