Application of Harmonic Analysis in the Preliminary Prediction of Air Temperature over Lagos and Abuja, Nigeria

Abstract

Harmonic Analysis technique has been employed in predicting the hourly air temperature variations over Lagos and Abuja, Nigeria. The variations in hourly air temperatures over the two stations are periodic and thus have strong tendency of being repeated the next day, if all other atmospheric variables are constant. It was observed that the variation in hourly air temperature in the two stations is dominated by the first harmonic, thus it fluctuates by one cycle with a period of 24 hours. Invariably, harmonic equations could be applied to hourly temperature prediction even on a large scale data. The maximum hourly air temperature occurred two hours on the average after the maximum solar irradiance has occurred in each station. It was found that the temperature of the air at a particular hour is dependent on that of the previous hour.

Modeling of diurnal pattern of air temperature in a tropical environment: Ile-Ife and Ibadan, Nigeria

“…Fourier series model is represented by the following equation (Panofsky and Brier 1960;Isikwue et al 2011) C i is the amplitude of the ith harmonic;…”

“…These methods include linear models (Parton and Logon 1981), simple curve fitting models based on sine or exponential analysis (Isikwue et al 2011) and more complex energy budget models (Goudrian and Waggoner 1972; Lemon et al 1972). Studies revealed that some of these models had been modified to account for the decay of air temperature at nighttime, while others are yet to be corrected (Ephrath et al 1996;Parton and Logon 1981).…”

“…They concluded that all methods worked well for daytime, but had limited success on nighttime stable atmospheric condition. In West Africa, Isikwue et al (2011) only employed Fourier series analysis in modeling the hourly air temperature variation over Lagos and Abuja, but no intercomparison with other existing models was carried out and the diurnal behavior of the simulated T a was not properly investigated. They concluded that the variation in hourly air temperature in the two stations was dominated by the first harmonics, thus it fluctuates by one cycle with a period of 24 h (Lidija 2007;Atsu and David 2000).…”