Accession Number : ADA138684

Title :   The Response of the Total Electron Content of the Ionosphere Over North America to the Total Solar Eclipse of 26 February 1979.

Descriptive Note : Environmental research papers,

Corporate Author : AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA

Personal Author(s) : Essex,E A ; Klobuchar,J A ; Philbrick,C R ; Leo,R

PDF Url : ADA138684

Report Date : 04 Oct 1983

Pagination or Media Count : 28

Abstract : Ionospheric total electron content (TEC) observations were carried out from eight stations during the total solar eclipse of 26 February 1979 over North America by monitoring changes in the Faraday rotation of the plane of polarization of vhf signals from geostationary satellites. Additionally, TEC data from ionospheric group-delay measurements were made at Vanderberg, Calif., from two 12-h synchronous NAVSTAR/Global Positioning System (GPS) satellites which crossed over the eclipsed region. Local times of totality of the eclipse in the ionospheric observed from the various stations ranged from 0730 h to 1400 h. Depletion of the ionospheric TEC from the non-eclipse average behavior varied up to a maximum of 40 percent for the ionosphere experiencing 100 percent eclipse. Maximum TEC depletion occurred, on average, 33 min after maximum obscuration. Most of the stations showed a rapid rate of depletion of TEC about 30 min after first contact, the rate of depletion reaching a minimum value at or before maximum obscuration. Before fourth contact was reached, the rate of increase of TEC generally had overshot the non-eclipse day average, gradually returning to that average after fourth contact. Ionosonde data showed that the peak density of the F region and the TEC varied by approximately the same amount at those stations for which the E region had formed before first contact of the eclipse. Slab thickness, a first order F-region shape parameter, was not significantly changed during the eclipse. (Author)

Descriptors :   *IONOSPHERE, *SOLAR ECLIPSES, ELECTRONS, DENSITY, VARIATIONS, STATISTICAL ANALYSIS, NORTH AMERICA

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE