Multifrequency riometer measurements at high latitudes
Abstract
The diurnal variation of the radio wave absorption measured by a riometer is the same kind at the frequencies 20 MHz, 27.6 MHz, 40 MHz and 50 MHz at the high latitude station Sodankyla (L=5.1) having two maxima, the one at midnight and another one in the morning side. The variation of n in the equation sub 1 A/sub 2 A = (f sub 2/f sub 1)n, where A = radio wave absorption (db) and f = used frequency, is studied. The daily and seasonal variation of n shows that n is smaller under sunlit conditions than during darkness, meaning that ionization is lower under sunlit conditions. No difference could be observed in comparing the values of n caused by precipitated electrons to nightside to those causing ionization in the dayside supporting the view that the energies of those particles ionizing the D region in the nighttime and daytime do not differ enough to be detected by this experiment.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- September 1978
- Bibcode:
- 1978STIN...7833285R
- Keywords:
-
- Radiation Measurement;
- Radio Waves;
- Riometers;
- Diurnal Variations;
- Electromagnetic Absorption;
- Ionization;
- Communications and Radar