A Grey Seasonal Index Model for Forecasting Groundwater Depth of Ningxia Plain

Table 1

The fitting value of Yinchuan Plain groundwater depth by Holt–Winters model (unit: m).

Month	Year
	2015	2016	2017	2018
1	2.06	1.69	2.00	2.09
2	2.27	2.19	2.48	2.65
3	2.63	2.53	2.71	2.89
4	2.69	2.62	2.75	2.92
5	2.75	2.68	2.81	3.07
6	1.94	1.90	2.05	2.27
7	1.71	1.70	1.81	2.10
8	1.55	1.59	1.69	2.01
9	1.91	1.81	2.07	2.23
10	2.46	2.18	2.58	2.94
11	2.61	2.57	3.02	3.16
12	1.53	1.56	1.79	1.85
MAPE	5.00