Winter Wheat Water Productivity Evaluated by the Developed Remote Sensing Evapotranspiration Model in Hebei Plain, China

Table 1

The average, standard deviation, maximum and minimum values of ETa in all 80 counties from 2001 to 2006 (mm).

Seasons	Mean	SD	Max.	Min.
2001	417.1	29.8	509.9	345.5
2002	446.0	29.9	506.1	356.3
2003	372.1	37.3	433.3	261.3
2004	392.9	32.0	456.2	336.6
2005	389.9	38.3	465.5	289.9
2006	400.1	49.1	516.3	303.7