Erratum to: Measurement and estimation of plastic greenhouse reference evapotranspiration in a Mediterranean climate

Erratum to: Irrig Sci (2010) 28:497–509 DOI 10.1007/s00271-010-0210-z

Following publication of the paper, the authors have detected a calculation error in the calibration of the FAO56 Penman–Monteith method used for estimating greenhouse reference evapotranspiration (ET_o). There is an error in the value of aerodynamic resistance (r _a) presented in the paper.

While a standard value of 150 s m⁻¹ was reported for the aerodynamic resistance (r _a) in the paper, we found subsequently that the correct value of r _a, that provides the best agreement between estimated and measured daily greenhouse ET_o values, as determined by minimizing the root mean square error (RMSE) with the SOLVER procedure (Microsoft^® Excel 2002), is 295 s m⁻¹. Measured ET_o data from 1993 and 1994 (without whitening), and from 2000 and 2001 (with whitening) were used for model calibration. With a fixed r _a value of 295 s m⁻¹, the FAO56 Penman–Monteith method was validated using measured ET_o values from 1995, 1997 and 1999 (without whitening), and from 2002, 2003 and 2004 (with whitening). The FAO56 Penman–Monteith with a fixed r _a of 295 s m⁻¹ correctly predicted measured values; it presented a slight underestimation of 6% without whitening (RMSE = 0.37 mm day⁻¹, MBE = −0.078 mm day⁻¹ and RE = −3.3%) and of 2% with whitening (RMSE = 0.38 mm day⁻¹, MBE = −0.047 mm day⁻¹ and RE = −2.3%).

Figure 6c and d, and Table 2 of the paper are presented here again since the values showed were affected by the change in the r _a value.

Fig. 6

Comparison between mean daily values of estimated and measured ET_o values in a plastic greenhouse with (from 2002 to 2004) and without whitening (from 1995 to 1999). ET_o values were estimated by FAO24 Pan method using a constant Kp value of 0.79 (a, b), FAO56 Penman–Monteith using a fixed aerodynamic resistance value of 295 s m⁻¹ (c, d). Each point corresponds with a daily ET_o value, averaged over a week, throughout a particular year

Table 2 Summary of statistics from the comparison between estimated (E, mm day⁻¹) and measured (O, mm day⁻¹) data of mean daily greenhouse ET_o with (2002–2004) and without whitewash (1995–1999) for FAO56 Penman–Monteith method using a fixed aerodynamic resistance value of 295 s m⁻¹

After making the above corrections, no further changes were required in the “Results”, “Discussion” and “Conclusions” sections of the paper.