Quarterly hour variation of surface refractivity and its relation to some atmospheric parameters in Ilorin, North-central Nigeria

The study investigated the quarterly variations in surface refractivity for Ilorin, North-Central Nigeria. Meteorological data, including air temperature, atmospheric pressure, and relative humidity, were collected from January 2000 to December 2002 at NIMET, Ilorin Airport. These meteorological parameters were averaged over three-hour intervals to determine specific time periods: sunrise (6-8 AM local time), midday (12-2 PM local time), sunset (5-7 PM local time), and midnight (11 PM-1 AM local time). The refractivity was then computed using the collected data. Notably, the quarterly surface refractivity was observed to be higher during the sunrise hours (0600-0800) compared to other quarterly hours (midnight, midday, and sunset). Additionally, variations in surface refractivity were primarily influenced by changes in relative humidity (moisture content). These findings provide valuable insights for predicting the effects of propagation on terrestrial communication links.