Open AccessAppearance and extension of airglow depletions
Author(s) -
Rajesh P. K.,
Liu J. Y.,
Sinha H. S. S.,
Banerjee S. B.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009ja014952
Subject(s) - airglow , equator , latitude , longitude , zonal and meridional , ionosphere , earth's magnetic field , geology , atmospheric sciences , night sky , low latitude , sky , substorm , geophysics , geodesy , physics , magnetosphere , magnetic field , astronomy , quantum mechanics
Previous observations using all‐sky imagers show that the field‐aligned airglow depletions propagate poleward in the low‐latitude and/or equatorial ionosphere. This paper reports the first observations of 630.0 nm depletions that appear to be extending equatorward during the premidnight hours in the all‐sky camera observations at the low‐latitude station Kavalur (12.5°N, 78.8°E; 3.9°N geomagnetic), India. The airglow imager and two ionosondes at the geomagnetic and off‐equator along the same longitude are used to understand the appearance and extension/development of depletions. The F layer peak height gradient along the meridional direction is obtained using the ratio of simultaneous 777.4 and 630.0 nm airglow intensities, and the observed apparent equatorward propagation of ionospheric depletions is explained in terms of such equatorial dynamics and photochemical processes, consistent with the poleward propagation previously reported.