Table 1. The description of statistics of the various driving factors and water resources from 1980 to 2015.

	Mean	Maximum	Minimum	Standard error	Coefficient of variance
Water resource	36.19	125.65	4.04	25.58	0.71
NDVI	299.93	417.83	229.68	42.13	0.14
Evapotranspiration	3.75	5.45	2.25	0.71	0.19
Precpitation	283.83	309.81	258.77	11.08	0.04
Temperature	252.79	266.43	244.21	5.73	0.02
Afforestation	591.67	907.39	256.52	170.56	0.29