The abundance of ions within the ionosphere makes it an important region for both long range and satellite communication systems. However, characterizing the complexity in the ionosphere within the equatorial region of Abuja, with geographic coordinates of 8.99° N and 7.39° E and a geomagnetic latitude of −1.60, and Lagos, with geographic coordinates of 3.27° E and 6.48° N and a dip latitude of −1.72°, is a challenging and daunting task due to the intrinsic and external forces involved. In this study, chaos theory was applied on data from both an HF Doppler sounding system and the Global Navigation Satellite System (GNSS) for the characterization of the ionosphere over these two tropical locations during 2020–2021 with respect to the quality of high-frequency radio signals between the two locations. Our results suggest that the ionosphere at the two locations is chaotic, with its largest Lyapunov exponent values being greater than 0 ($0.011\le \lambda \le 0.041$) and its correlation dimension being in the range of $1.388\le D_2\le 1.775$. Furthermore, it was revealed that there exists a negative correlation between the state of the ionosphere and signal quality at the two locations. Using transfer entropy, it was confirmed that the ionosphere interfered more with signals during 2020, a year of lower solar activity (sunspot number, 8.8) compared to 2021 (sunspot number, 29.6). On a monthly scale, the influence of the ionosphere on signal quality was found to be complicated. The results obtained in this study will be useful in communication systems design, modelling, and prediction.

This study investigated the long-term changes in the total column ozone (TCO) over Nigeria using measurements retrieved from the ozone (O3) multi-sensor reanalysis (MSR). It assessed the spatial variability of TCO in Dobson Unit (DU), its monthly distribution, and interannual variability, and identified trends at these time scales over three decades (1981–2010) using the Sen’s slope estimator. The results of these analyses reveal that over the study area, the O3 maximum and minimum concentrations are 248 DU and 268 DU, respectively, producing an average range of about 255 DU. During the dry season, TCO values were found to be less than 250 DU across the country but greater than 250 DU during the wet season. Furthermore, the interannual O3 characteristics uncover dynamic oscillating features, which can be attributed to the influence of a combination of many atmospheric processes, e.g., the wind pattern and stratospheric intrusion. The contribution of sunspot number, Southern Oscillation Index, and Quasi Biennial Oscillation (QBO) at 10 hPa and 30 hPa to TCO values across Nigeria was also investigated. QBO at 10 and 30 hPa showed statistically significant correlation values with TCO over the region.

Lassa fever, a viral hemorrhagic disease endemic to West Africa, presents significant public health challenges due to its environmental sensitivity and hig

This paper examined the diurnal variation of the doppler frequency shift (DFS) of a trans-ionospheric high frequency (HF) radio wave signal within the equatorial ionospheric anomaly region. Within the framework of the International Space Weather Initiative, a multi-institutional cooperation set up a HF transmitter and receiver systems at the Space Environment Research Laboratory, Abuja, Nigeria (Geographic: 7.39°E, 8.99°N; dip latitude – 1.37°) and the Department of Physics, University of Lagos, Nigeria (Geographic: 3.27°E, 6.48°N; dip latitude – 1.72°) respectively. Medium-term digital recording of waveforms of trans-ionospheric HF radio signals were obtained from the experimental observation to investigate the diurnal variation of DFS along Abuja – Lagos radio path between 2019 and 2022. The DFS exhibited diurnal variation with maximum at sunrise (5:00–7:00 UT) and sunset (17:00–18:00 UT) periods, as well as day-to-day variability which was attributed to day-to-day variability in the dynamics of flow of plasma in the Equatorial Ionization Anomaly region, meridional neutral winds and local atmospheric conditions in the thermosphere. A large spread of amplitudinal variations of DFS was observed in post Sunset and post-midnight period, while the observed small variations of DFS in midday and afternoon hours is attributed to the displacement of reflection point downward.

Ground-level ozone presents a clear and present danger to humans, plants, and environment. However, stratospheric ozone protects life on earth from the harmful