Seasonal Dynamics of Solar Radiation and Meteorological Parameters in a Tropical Nigerian Station

Abstract

Temporal variation of solar radiation with prevailing meteorological parameters focused on a specific location in the south-west Nigeria to provide detailed information required for climate studies and agricultural activities. Hourly and monthly solar radiation trends were analyzed using the variations in the temperature, relative humidity and wind speed from 2010 to 2013. This was with the purpose of determining the correction in the monthly trends of the solar radiation and meteorological parameters in Akure, south-west, Nigeria. Statistical analysis using Open Air project for R-statistics and the multiple linear regression (MLR) were carried out to establish correlation between solar radiation and prevailing meteorological parameters. Solar radiation has more significant impact on other meteorological parameter in the wet season at Akure while it drags other parameters with 1 – 2 months lag in the dry season. In the month August, which was characterized by the peak wet season, the station experiences rainfall break, extremely cloudy overcast and dominance of southwesterly wind. The cloudy atmosphere interrupts the incoming solar radiation with consequent effect of extremely humid and cold air temperature. This was why the low solar radiation aligned with high relative humidity and high wind speed in August while the temperature was the lowest. However, in dry season, the lag was as a result of onset of rainfall characterized by withdrawal of dry and cold northeasterly wind which interfered with response of boundary later to incoming radiation due to irregular heavy rainfall and rapid evaporation at this period. The results clearly aligned with predominant weather patterns in the tropical station influenced by back-and-forth movement of inter-tropical discontinuity during transition from dry to wet season.