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%).