STATISTICAL EVALUATION OF HYDRO-METEOROLOGICAL DATA: A CASE STUDY OF ISHIAGU IN SOUTH-EAST ZONE NIGERIA

For any Engineering project to be efficient, it must be based on consistent and reliable data with good analysis. Reliability, especially for hydro-meteorological data depends on the method of collection, analysis and storage. Ishiagu weather data has been collected since the inception of the school of agriculture in the town in 1997 to date. Statistical analysis of the randomly varying data to check for their consistency and reliability is necessary before use. In this regard, the monthly data set is analysed for annual mean, trends and seasonal distribution pattern. A significant finding of this analysis is that the monthly rainfall has bimodal distribution with peaks in July and September. For the temperature of the area, it showed a sinusoidal pattern due to the seasons and this also reflects on the relative humidity of the area. A regression analysis of the three data of rainfall, temperature and relative humidity indicates a coefficient of correlation of r = 0.3, t = -0.40 and rh = -0.67. Because of the low state of the coefficient of correlation of the three parameters it may be necessary to recheck with either power, exponential or polynomial functions. From the determination of frequency of extreme events using Gumbel distribution, the highest annual rainfall value is determined to have a return period of less than 20years and the 17years records also was adjudged adequate.