Downscaling of Open Coarse Precipitation Data through Spatial and Statistical Analysis, Integrating NDVI, NDWI, Elevation, and Distance from Sea

Table 4

Stepwise regression parameters of Group 3 (models based on NDVI, distance, and altitude) and Group 4 (models based on NDWI, distance, and altitude).

(a) Correlation, standardized and unstandardized coefficients

Models	Years		Sig.	Unstandardized coefficients				Standardized coefficients
				NDVI	NDWI	Distance	Elevation	NDVI	NDWI	Distance	Elevation
Group 3: stepwise (NDVI, altitude, and distance)	1999	0.77	0.000	887	—	−0.14	0.07	0.74	—	−0.12	0.34
	2000	0.81	0.000	997	—	−0.04	0.05	0.82	—	−0.03	0.23
	2001	0.83	0.000	1587	—	−0.10	0.09	0.83	—	−0.05	0.24
	2002	0.83	0.000	1329	—	−0.15	0.10	0.79	—	−0.09	0.33
	2003	0.85	0.000	1377	—	−0.14	0.08	0.85	—	−0.07	0.21
	2004	0.80	0.000	1506	—	−0.15	0.11	0.81	—	−0.07	0.27
Group 4: stepwise (NDWI, altitude, and distance)	1999	0.56	0.000	—	1213	−0.30	0.08	—	0.51	−0.26	0.37
	2000	0.55	0.000	—	1367	−0.26	0.09	—	0.51	−0.21	0.37
	2001	0.64	0.000	—	2401	−0.26	0.10	—	0.68	−0.13	0.28
	2002	0.56	0.000	—	1888	−0.34	0.13	—	0.54	−0.21	0.42
	2003	0.79	0.000	—	2351	−0.23	0.09	—	0.74	−0.12	0.25
	2004	0.72	0.000	—	2553	−0.16	0.11	—	0.72	−0.07	0.26

(b) AIC and statistical tests

Models	Years						Tolerance				AIC
		NDVI	NDWI	Distance	Elevation	Sig.	NDVI	NDWI	Distance	Elevation
Group 3: stepwise (NDVI, altitude, and distance)	1999	40,20	—	−5,81	17,42	0,000	0,768	—	0,634	0,696	9588,57
	2000	48,60	—	−1,75	12,56	0,081	0,765	—	0,636	0,687	9543,35
	2001	50,95	—	−2,70	14,01	0,007	0,788	—	0,644	0,719	10307,59
	2002	49,93	—	−5,43	20,24	0,000	0,758	—	0,624	0,698	9853,88
	2003	55,81	—	−4,15	13,22	0,000	0,770	—	0,626	0,719	10167,80
	2004	47,59	—	−3,71	15,04	0,000	0,759	—	0,622	0,704	10518,16
Group 4: stepwise (NDWI, altitude, and distance)	1999	—	19,13	−9,17	12,93	0,000	—	0,745	0,655	0,636	10199,65
	2000	—	18,58	−6,86	12,77	0,000	—	0,791	0,653	0,704	10398,79
	2001	—	29,46	−5,18	11,68	0,000	—	0,792	0,650	0,713	10911,19
	2002	—	21,05	−7,47	15,94	0,000	—	0,737	0,606	0,690	10676,36
	2003	—	34,09	−4,79	11,32	0,000	—	0,754	0,612	0,719	10756,70
	2004	—	31,57	−2,85	11,20	0,004	—	0,700	0,577	0,672	10971,84

Sig.: signification test of distance from sea at 2-tailed .