基于Z比分数的参考作物腾发量计算方法优选

Optimization of Reference Crop Evapotranspiration Calculation Methods Based on Z-score

参考作物腾发量(ET0)是计算作物需水量的关键,是进行农田水分管理和灌溉预报的主要参数。但不同ET0计算方法的结果存在明显差异。用能力统计量Z比分数,对FAO56Penman-Monteith、Hargreaves-Samani、Irmark-Allen拟合和Priestley-Taylor四种常用ET0计算方法在不同天气条件下的计算结果精度进行了对比分析。结果表明,Priestley-Taylor与FAO56Penman-Monteith方法的计算结果在精度上具有较高的一致性,与有关文献结果相吻合,其中前者精度略佳。且Z比分数参数受极端值的影响较小,计算简便、适用性强,克服了常规方法公式繁杂、编程实现困难的缺点,说明Z比分数法能够更好地适用于ET0计算方法的优选。研究结果可为农业水土工程领域有关参数计算与测定方法的优选提供借鉴。

Reference Crop Evapotranspiration （ETu） is the key to calculate crop water requirement and the main parameter for the farmland water management and irrigation forecasting. But the results in different calculation methods of ETo are obvious different. Z-score, an ability statistics in robust analysis, is introduced in the paper to analyze the accuracy of the four kinds of ETo calculation methods, including FAO56Penman-Monteith, Hargreaves-Samani, Irmark-Allen fitting and Priestley-Taylor. The results of ETo under different weather conditions show that the results calculated by Priestley-Taylor and FAO56Penman- Monteith methods have rather higher grade of coincidence with related literatures, and the former is slightly better in accuracy~ the parameter of Z-score is less affected by the extreme values, simple to calculate, strong in applicability; the Z-score method overcomes the problems of com- plicate in formula and the difficulties in programming for traditional methods. So, it can be well used for optimization of ETo calcula tion methods. The research result provides a reference for the optimization of the calculation and determination methods for relevant parameters in the field of agricultural water and soil engineering.