Evaluation of Seven Gap-Filling Techniques for Daily Station-Based Rainfall Datasets in South Ethiopia

Table 2

Performance evaluation results of gap-filling techniques in Areka station before and after empirical quantile mapping plus (EQM⁺).

Performance evaluation criteria	Gap-filling techniques
	SAM	NRM	CCW	IDW	MLR	EQM
Before empirical quantile mapping plus
MAE (mm)	4.16	4.14	4.15	4.21	4.67	5.40
RMSE (mm)	7.96	7.98	7.96	8.04	7.75	9.70
SS (unitless)	0.12	0.11	0.12	0.10	0.16	−0.31
R (unitless)	0.29	0.29	0.29	0.29	0.29	0.22
After empirical quantile mapping plus (EQM^+)
MAE (mm)	5.01	4.98	5.00	5.06	5.74	6.29
RMSE (mm)	8.11	8.12	8.10	8.21	7.99	10.08
SS (unitless)	0.08	0.08	0.09	0.06	0.11	−0.42
R (unitless)	0.29	0.29	0.29	0.30	0.27	0.22

MAE, RMSE, SS, and R are mean absolute error, root mean square error, skill score, and Person’s correlation coefficients, respectively.