Applicability and improvement of different evapotranspiration methods of reference crops in Jiangxi Province

• Published in: Theoretical and applied climatology 2022, Vol.147 (1-2), p.73-86
• Main Authors: Lu, Xianghui, Zhang, Haina, Han, Yixiu, Bai, Hua, Li, Erhui
• Format: Article
• Language: English
• Subjects: Accuracy; Agricultural industry; Analysis; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Climate science; Climatic data; Climatology; Crops; Earth and Environmental Science; Earth Sciences; Evapotranspiration; Humidity; Mathematical analysis; Mean square errors; Methods; Original Paper; Parameters; Relative humidity; Root-mean-square errors; Waste Water Technology; Water Management; Water Pollution Control; Weather; Weather stations; Wind; Wind speed
• ISSN: 0177-798X; 1434-4483
• DOI: 10.1007/s00704-021-03806-7

To achieve accurate evaluation of evapotranspiration of reference crops (ET0) in Jiangxi, China, in the absence of systematic climatological data, with reference to the FAO-56 Penman–Monteith (P-M) equation, the Priestley-Taylor (P–T) method, the Makkink method, the Hargreaves-Samani (H–S) method, the Irmak-Allen (I-A) method, the Penman1948 (48PM) method, the Penman-Van Bavel (PVB) method, the Baier-Robertson (B-R) method, the improved Baier-Robertson (M-B-R) method, the Schendel (Sch) method, the Turc method, the Jensen-Haise (J-H) method, and the Brutsaert-Stricker (B-S) method were used to evaluate the daily climatological data collected by 26 weather stations in Jiangxi, China, and 17 weather stations in adjacent provinces. The results were compared with each other and parameter rate determination was conducted. The results indicated that the Turc method exhibited optimized applicability before parameter rate determination and the average root mean square error (R MSE ) and the average normalized root mean square error (N RMSE ) by this method were 0.39 mm/d and 0.157 mm, respectively. However, parameter rate determination led to negligible improvement in accuracy for this method. The Turc method could be directly applied in Jiangxi (except Nanchang). For special distribution of error after parameter rate determination, all methods exhibited significant errors in Northern Jiangxi. Herein, the 48PM method and the B-S method showed good applicability after parameter rate determination and R MSE and N RMSE of data by these methods ranged in 0.06 ~ 0.34 mm/d and 0.08 ~ 0.27, 8 ~ 27%, respectively, and their d-indices were close to 1. The annual over-estimations in weather stations in Jiangxi were below 30 mm. In the absence of data about relative humidity and wind speed, the P–T method was an appropriate simplified method for Jiangxi. In this case, α was slightly lower than the default value (1.05 ~ 1.18), R MSE was within 0.21 ~ 0.66 mm/d, and N RMSE was within 0.08 ~ 0.308 ~ 30%. Accuracy of R MSE , d-index, and N RMSE of data by the P–T method, the I-A method, and the PVB method was consistent with all stations, while that by the Mak method was slightly lower, which could be attributed to severe over-estimation in July and August. R MSE of the H–S method, the B-R method, the M-B-R method, the J-H method, and the Sch method were above 0.75 mm/d and these methods were not suitable for accurate evaluation of ET0 in Jiangxi, China. The annual ET0 was calcu