Estimation of Diffuse Solar Radiation for Selected Cities in Nigeria

Table 1

Analysis of estimation (proposed and existing) models using five-year (2001–2005) monthly mean daily data obtained for the study locations.

Models	Error terms
	MBE (kWh/m^2/day)			RMSE (kWh/m^2/day)			TS*
	Abuja	Benin City	Katsina	Abuja	Benin City	Katsina	Abuja	Benin City	Katsina
Present study	−0.0012	−0.0008	−0.0097	0.0397	0.0340	0.0901	0.1021	0.0814	0.3578
Liu and Jordan [1]	−0.1464	−0.2374	−0.0179	0.2348	0.2604	0.1366	2.6444	7.3567	0.4375
Page [2]	0.0647	0.0544	0.0540	0.0931	0.0828	0.1082	3.2072	2.8978	1.9114
Iqbal [3]	0.3849	0.2582	0.5136	0.4202	0.2964	0.5215	7.5819	5.8834	18.9162
Erbs et al. [6]	0.8927	1.1042	0.5246	0.9393	1.1099	0.5661	10.1357	32.5672	8.1787

* 𝑡_{𝑐(11,0.025)}=1.96.