Abstract-The diurnal and seasonal variation of surface refractivity over Nigeria was studied using four years in-situ meteorological data from eight location over Nigeria. At all the stations studied, it was observed that the diurnal refractivity variation was caused majorly by the dry term in the rainy season and the wet term is the major cause of refractivity variation in dry season except Sokoto and Jos. In Sokoto the result was found to be opposite and it is attributed to the fact that in dry season the humidity is almost close to zero while in rainy season the pressure seems to be almost constant but the temperature fluctuates rapidly and consequently the humidity. The variation pattern in Jos is as observed because of the altitude (∼ 1000 m above sea level). At this altitude pressure variation seems to be insignificant. The result also show that the surface refractivity generally have higher value during rainy season than dry season at all location studied. The result also show that the value of surface refractivity increases from arid region in the north to the coastal area in south. The result also show that the diurnal refractivity variation is basically a function of local meteorology and while seasonal variation is caused follows the climatic condition.

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The average seasonal variations of surface radio refractivity pressure, temperature and relative humidity made across Yola (9 N, 6 o 45' E), Lagos (6 o 27' N, 5 o 12' E), and Port measurement was made using wireless automatic weather station installed at the surface of each station under study. The study utilized three years of meteorological data measured from January 2010 to December 2013 to calculate the surface radio refractivity using empirical form recommended by the International Telecommunication Union (ITU that the average value of surface radio refractivity showed seasonal variations with high values during the rainy season and low values during the dry season surface radio refractivity of 242N-Lagos station. The result also shows that climatic condition is the force behind the seasonal variations of surface radio refractivity in all study stations.

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Aim and Objective Despite the growing concerns about the relationship between exposure to radiofrequency radiation (RFR) and detrimental health effects due to the changes in biological processes of experimental animals, there is still ongoing debate on the significance of these findings in causing significant public health problems with the growing advancement in internet technology. The aim of this study is to review existing literature on the effects of high RFR on wistar rats. Method A search was conducted on Google scholar and PubMed to identify relevant peer-reviewed articles to be included into the review. Studies eligible for inclusion included free full text articles on wistar rats exposed to ≥ 2.45GHz RFR conducted in the past 5 years. Studies included in this review were written or transcribed in English language. From 286 titles, 36 eligible studies were included in the review and assessed for quality using the Strengthening the Report of Observational Studies in Epidemiology – Veterinary Extension (STROBE-Vet) quality assessment tool. Results Studies included in this review generally had good quality (>60%) based on the STROBE-Vet assessment. This review identified numerous biological changes in wistar rats exposed to high RFR including variations in biochemical, cholinergic, genetic, histopathologic, psychological, optical, and dermatological parameters. In this review, studies identified variations in protein and liver enzymes while high RFR was found to induce oxidative stress and cellular damage of exposed wistar rats compared to the unexposed groups. This was seen in the changes in protein, lipids, enzymatic and non-enzymatic antioxidants. Studies also identified changes in expression of genes and neurotransmitters with imbalance in hormones. In addition, this review identified structural changes of cells, tissues and organs indicative of apoptosis, damage and death. Exposed rats were identified to have behavioral changes indicative of anxiety and memory decline while studies identified optical and dermatologic changes in exposed rats compared to the unexposed. Conclusion With numerous biological changes identified in wistar rats exposed to high RFR, there is an increasing risk of detrimental health events giving the advancement in internet technology and limited regulations to control exposures to RFR. Therefore, studies should be conducted to identify strategies to mitigate human exposure to RFR while policies are developed and enforced to protect human health.