Ohanuna C, Vincent E Weli, Moses O Nwagbara
The study assessed the trends and characteristics of atmospheric visibility over selected cities in Nigeria. Visibility, rainfall, relative humidity, windspeed and temperature data of 36 years (1982-2017) were obtained from the Nigeria Meteorological Agency Abuja for the selected meteorological stations and computed. Descriptive (mean and standard deviation) and inferential statistics (Analysis of Variance (ANOVA) and multiple regression) were used for the data analysis. Results revealed that visibility decreased over the years in all the selected study locations with the exception of Badagry which recorded an 18.09 m annual increase in visibility. The annual trend of rainfall and temperature showed an increase in temperature and rainfall in all the cities studied except Owerri which witnessed a 5.58 mm decrease in rainfall. The student t-test statistics revealed a statistically significant difference in visibility, rainfall, windspeed and relative humidity between the wet and dry seasons in the selected cities. The study also showed that the relationship between visibility and wind speed, temperature, rainfall and relative humidity was statistically significant (R=0.904; F=75.152; p=0.000) as the p value is less than 0.05. In the light of the increasing deterioration of visibility over the study area, the study recommends an urgent need to develop early warning systems for monitoring, risk assessment, mitigation and response to the vagaries of the ever-fluctuating visibility and weather parametersn.