Sura I. Gburi
Abstract: In this research the ionospheric sporadic E (Es) layer parameters (foEs, fbEs and h'Es) are studied at mid latitude Yamagawa, Japan (31oN, 130oE) station for a long period (2010-2016) during quiet and disturbed conditions. The data has been analyzed to study the seasonal and annual variations in the occurrence of Sporadic E along the period selected, from results it is found that the maximum values of fbEs and foEs are observed during the summer while the minimum values are observed during winter. About h'Es parameter the maximum values are recorded during the spring and the minimum values are recorded in winter. The variability between foEs and fbEs is studied, it is revealed that there is a correlation between the two parameters foEs and fbEs for all seasons except in summer foEs higher than fbEs also in sunrise and sunset. The occurrence of the sporadic E layer in mid latitude shows that it changes from year to year, strong dependence on local time and season, also found a very good correlation coefficient between fbEs and foEs ? 0.9 for all season. And the distribution of frequency ratio is polynomial four degree.
Keywords: Sporadic E, blanketing frequency, Critical frequency