Accession Number : ADA324435

Title :   Investigation of the Ionospheric Short-term Variability.

Descriptive Note : Final rept. Jan-Dec 96,

Corporate Author : TECHNION - ISRAEL INST OF TECH HAIFA ASHER SPACE RESEARCH INST

Personal Author(s) : Houminer, Zwi ; Shaviv, G.

PDF Url : ADA324435

Report Date : 15 FEB 1997

Pagination or Media Count : 73

Abstract : Both the total electron content of the ionosphere (TEC) and the critical frequency of the F2 layer (foF2) exhibit large day-to-day variations during quiet and active geomagnetic periods. It is of great interest to ascertain whether good correlation exists between TEC daily variability about the monthly mean and foF2 variations. With the availability of the global GPS constellation to provide instantaneous time-delay values such a correlation may enable the improvement of HF short-term predictions using passive monitoring of TEC. To determine the correlation one year of TEC and foF2 data were collected from June 1995 until May 1996. The TEC data was determined from GPS time-delay measurements at Matera, Italy, obtained from the data base of the International GPS Services for Geodynamics. The foF2 measurements came from Rome, Italy. The analysis showed, that for large percentages of the time very good correlation exists between TEC and foF2 short-term variations. The correlation coefficient varies from 0.7 - 0.8 during the summer months to about 0.5 - 0.6 during the winter. A study of the diurnal dependence of the correlation indicates that better correlation exists during day-time than night-time. The high correlation between TEC and foF2 indicates that real-time ionospheric HF prediction improvements are feasible when using transionospheric time-delay measurements.

Descriptors :   *ELECTRON DENSITY, *F REGION, *IONOSPHERIC PROPAGATION, DATA BASES, ISRAEL, GEOMAGNETISM, HIGH FREQUENCY, REAL TIME, AUTOCORRELATION, SEASONAL VARIATIONS, GLOBAL POSITIONING SYSTEM, RADIO SIGNALS, DAILY OCCURRENCE, DIURNAL VARIATIONS, CROSS CORRELATION.

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE