IONOSPHERIC EFFECTS OF THE SOLAR ECLIPSE OF MARCH 9, 1997, AS DEDUCEDFROM GPS DATA

This paper presents data from first measurements of total electron con tent (TEC) and its gradient during the solar eclipse of March 9, 1997, obtained with the GPS-radio interferometer at Irkutsk The interferome ter consists of three receivers (one Turbo-Rogue SNR-8000, and two Ash tech 2-12) located at the vertices of a triangle and spaced by about 3 -5 km. The measured TEC variations are indicative of profound changes in the ion production process in the ionosphere attendant on the solar eclipse, simultaneously in a large volume of space with a radius of a t height 300 km at 300 km altitude. The delay of a minimum value of TE C with respect to the maximum phase of eclipse at 300 km altitude was about 10 min, and the depression depth of TEC growth varies from 1 div ided by 3x10(16)m(-2). By analyzing the data on TEC gradient variation s, one is led to conclude that the depression of TEC growth during the eclipse is essentially independent of the longitude and of the latitu de (within the observation ranges 52+/-6 degrees N and 104+/-11 degree s E).