3.6 Dominant factors affecting the seasonal variation in lysimeter ET measurements
BRT model indicated that the net radiance was the dominant factor controlling the seasonal variation in measured ET during the whole study period, accounting for 50.34% of total variability, followed by mean air temperature (25.63%), RH (4.96%), VPD (4.91) and Rs (4.33%) (Fig.7a). Factors Ra, G, TD and WS made little contribution to the seasonal variation in measured ET. During the growing season, the net radiance remained the main control of seasonal variation in measured ET (Fig. 7b), accounting for 39.85% of total variability, followed by VPD (14.57%), T (9.37%), Rs (7.91%) and RH (6.45%). However, the seasonal variation of measured ET in non-growing season was dominated by T (Fig. 7c), accounting for 29.35% of total variability, followed by RH (17.28%), Rn (16.33%) and Ra (9.72%).