Abstract: In this research article, the authors have implemented the Exploratory Data Analysis (EDA) techniques to examine the deviation of the monthly median noon and midnight values of the critical frequency of F2 layer ionosphere (i.e. f0F2) at the Wakkanai station (45.39°N, 141.68°E), Japan, during sunspot cycle 21st (1976-1986) and 23rd (1996-2008). Primarily, univariate analysis has been done, which shows the variations in f0F2 at different local times, seasons and in the range of sunspot numbers (SSN), in which winter and semi-annual anomalies are detected in the months of December and March respectively. Secondly, the regression analysis is being used as a bivariate data analysis. The results proved a significantly nonlinear relationship exists between f0F2 and SSN. In both solar cycles, saturation effects are seen in the month of March during the noontime period and immensely in June during the midnight time. The behavior of the ionosphere has been studied for different latitudes, seasonal effects and sunspot dynamic conditions, in which this paper plays an essential role in it.
Keywords: Sunspot number, Ionosphere, f0F2, Winter anomaly, Semi-annual anomaly, Saturation effect.