Variation of Surface Radio Refractivity in Minna, North Central Nigeria

The radio refractivity at the surface is vital in the design and planning of terrestrial radio links in the lower atmosphere (troposphere). For this reason, measurement of atmospheric parameters (Pressure, Temperature and Relative Humidity) were obtained in Minna � (936�50�N and 633�25�E) � to determine the surface radio refractivity. The measurement was taken by positioning wireless meteorological sensors at the ground surface. The measurement was made at 30 minutes interval for a complete 24 hours cycle. The diurnal and seasonal variation of the surface radio refractivity were studied using two years of data measured from January 2008 to December 2009. The result obtained show that the value of surface radio refractivity is relatively high during the rainy season (April-October) and low during the dry season (November-March). The results obtained also show that the diurnal variation during the dry season is attributed to the dry term of refractivity, while the diurnal variation during the rainy season is attributed to both the dry and wet term.