Temperature variability, intensity of wind speed and visibility during harmattan in Makurdi Town, Nigeria
The study assessed the connections between temperature variability, intensity of wind speed and their effect on visibility of Makurdi town during the harmattan season. Data on mean monthly temperature of harmattan months of November, December, January and February (2001 to 2011), Wind speed and visibility records for the same period were obtained from the Nigeria Metrological Agency Makurdi. Monthly accident records from 2009 to 2011 were acquired from the Federal Road Safety Commission to compare accident rates within and outside the harmattan period. The data for this study was analysed using tables, bar graphs and Product moment correlation. The result showed that temperature within the harmattan months has fluctuated but showed an increasing trend in all the months. The rate of temperature increase across the months showed highest rates in the month of January, followed by February, November and lastly December. A correlation of temperature and harmattan wind speed shows a weak negative relationship value of - 0.29. The result implies that the speed of harmattan wind in Makurdi is not dependent on temperature within the environment; the speed is determined by the general regional wind movement pattern. Environmental friendly practices like planting of trees, gardens and lawns, tiling of the roads and water sprinkling can help curb the effects of the harmattan dust.
Keywords: Harmattan, visibility, variability, wind speed, pressure gradient