Browsing by Author "JOYCE, BOLANLE ADEMOLA"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Open Access
    The Prevalence Of Thunder And Its Effect On Rainwater Quality In Obafemi Awolowo University Campus, Ile-Ife, Nigeria
    (2012) JOYCE, BOLANLE ADEMOLA
    This study investigated the pattern of temporal variation in the prevalence of thunder rain and lightning in ObafemiAwolowo University, Ile – Ife, Osun State, Nigeria. It also investigated the chemical composition of rainwater with thunder and without thunder with the view of determining the effect of thunder and lightning on rainfall characteristics. The study was carried out in two sites within ObafemiAwolowo University from May, 2008 to April, 2009. Sample of every freefall rain was collected at each site using a plastic bowl of diameter (320 mm), stationed on one meter high wooden platform. Rainfall duration, rain amount, number of thunderclaps, and number of lightning were determined during each rain event. Rainfall rate and the interval between successive rainfall events were also recorded. Rainfall duration was estimated by the time between the beginning and the end of each rain event (in minutes) while rain amount was determined using the measuring cylinder. Rainfall rate (mm/min) was thus calculated from the total amount of rainfall divided by rain duration. The total number of thunder and lightning were recorded by sound and sight respectively. Electrical conductivity, pH, total alkalinity, total acidity, total hardness and nine major and minor ions (Ca2+, Mg2+, K+, Na+, HCO3-1, Cl- ,NO3-1, SO42-, PO43-) of water sample collected during the rain event were determined using standard methods. The data obtained were analysed using descriptive statistics, ANOVA, regression, correlation, and cluster analyses. Peak thunder events were recorded between 1200-1800 hrs (i.e. afternoon) and least between 0600-1200 hrs (morning). Over the annual cycle, the incidence of thunder was highest (7±0.77) in October (late rainy season), relatively high (5±0.41) in May (early rainy season) and lowest (0±00) in January (peak of dry season). Rain with thunder was more acidic (pH=5.50±0.04) but of shorter duration (34.6±2.1mins) than rainwater without thunder (pH=5.78±0.06; 43.2±3.3min respectively). Rain with thunder was also higher in nitrate (0.16±0.03mgL-1) and sulphate (0.05±0.02mgL-1) than rain without thunder (nitrate=0.03±0.04mgL-1 and sulphate=0.04±0.07mgL-1) while the reverse occurred for other parameters (Total alkalinity 1.57±0.19mgL-1, Total acidity 6.16±0.50mgL-1, Total hardness 1.83±0.22mgL-1, Calcium 0.43±0.07mgL-1, Magnesium 0.14±0.04mgL-1, Potassium 0.45±0.00 mgL-1, Sodium 0.00±0.00mgL-1, Hydrogen ion 2.70±0.42mgL-1, Bicarbonate 1.67±0.24mgL-1, Chloride 0.93±0.07mgL-1, Phosphate 0.00±0.00 mgL-1). Rainfall duration was not significantly (p > 0.05) correlated with prevalence of thunder. The study concluded that rainfall pattern in the study was of convectional type and that thunder and lightning significantly lower the pH and electrolytic conductivity of rain.