Daytime F layer trough observed on a macroscopic scale

Technical Report · Sun Mar 01 04:00:00 EST 1987

OSTI ID:6495587

Whalen, J A

This paper reports a new technique of observing the high-latitude ionospheric trough which defines its continuity in space and time on a macroscopic scale not previously possible. Vertical ionospheric soundings provide the observations in the midday-to-evening sector where to signature of the trough is found to be a bite out of a factor of 3 10 in the diurnal distribution of the solar-produced electron density at the F-layer maximum. The data base employed is that produced by the extensive array of ionospheric sounders operating at high latitudes in the northern hemisphere at solar maximum. The worldwide extent, high density, simultaneity, and continuity of these measurements make possible the description of the trough for the first time as an integral, spatial entity in its entire daytime extent and UT duration. The technique is demonstrated in studies of 4 days that span the range of activity for the month. On the most disturbed day, the daytime trough is continuous in magnetic latitude remains nearly stationary in this frame of reference for a duration of 14.5 hours UT. A snapshot constructed from multiple simultaneous observations on this day shows the trough to have a continous length of 6000 km and an areas of >4 million sq km. The trough is found to rotate clockwise to earlier magnetic local time by 5.5 hours and to expand equatorward in magnetic latitude by 20/sup 0/ as activity increases from quiet to disturbed. Activity dependence and morphology are consistent with other observations that the trough locates rapid westward convection within the dusk convection cell.

• Research Organization: Air Force Geophysics Lab., Hanscom AFB, MA (USA)
• OSTI ID: 6495587
• Report Number(s): AD-A-178386/9/XAB; AFGL-TR-87-0096
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DISTRIBUTION
EARTH ATMOSPHERE
EARTH PLANET
ELECTRON DENSITY
ELECTRONIC EQUIPMENT
EQUIPMENT
F REGION
GEOGRAPHICAL VARIATIONS
GEOMAGNETIC FIELD
IONOSONDES
IONOSPHERE
LATITUDE EFFECT
MAGNETIC FIELDS
NORTHERN HEMISPHERE
PLANETARY IONOSPHERES
PLANETS
RADIO EQUIPMENT
SOLAR ACTIVITY
VARIATIONS