MODELS OF HOURLY DRY BULB TEMPERATURE AND RELATIVE HUMIDITY OF KEY SELECTED AREAS IN NIGERIA FOR ENGINEERING APPLICATIONS

Abstract

Hourly meteorological data of both dry bulb temperature and relative humidity for 18 locations in Nigeria for the period 1995 to 2009 were analysed to obtain the mean monthly average and monthly hourly average of each of the two meteorological variables for each month for each location. The difference between the maximum and minimum values of the monthly hourly averages of each variable for each month were also computed and taken as the range of that variable for each location. The monthly hourly averages of each variable for each month and for each location were standardized by subtracting the mean monthly average from it and dividing it by the computed range and plotted against time. Twelve curves for the months of the year were obtained for each of the eighteen locations making a total of 216 curves for each meteorological variable. The average of the 216 curves was used to develop Fourier series for each variable. Mean Forecast Error (MFE), Mean Absolute Deviation (MAD) and Mean Absolute Percentage Error (MAPE) were used to compare results of the models with results from the meteorological data. The agreements between them were very good. The values of the mean monthly averages and the ranges for dry bulb temperature and relative humidity were presented in Tables so that these input values that need to be fed into the models are readily available.  Since the eighteen locations are well spread out over Nigeria, it is appropriate to use these models as inputs in computer programs for simulation of refrigerator, air conditioning systems and internal combustion engines operating anywhere in Nigeria.

http://dx.doi.org/10.4314/njt.v35i2.17