**5. Conclusion**

126 Solar Radiation

We engaged both Page (1964) and Klein (1977) models to study the variation of diffuse solar radiation for Ikeja, Ilorin, Ibadan, Port Harcourt and Benin. Large variations in the intensities of diffuse radiation due to cloudiness have been indicated as stated earlier.

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

Months

Fig. 4.2. Monthly variation of diffuse solar radiation using Page model for selected stations

Months

Fig. 4.1. Monthly variation of diffuse solar radiation using Klein model for selected stations

5

5

6

Latitudes

7

(Ikeja, Ilorin, Ibadan, Port Harcourt and Benin)

(Ikeja, Ilorin, Ibadan, Port Harcourt and Benin).

6

Latitudes

7

The global solar radiation incident on a horizontal or inclined surface is estimated by establishing the sky conditions. Monthly variation of clearness index (KT), diffuse ratio (KD), Temperature and the relative sunshine duration (RS) were employed in this study. Klein and Page model were used in this study to examine the variation of diffuse solar radiation for Iseyin, as no station in Iseyin measures diffuse solar radiation.
