基于Hargreaves的四川地区参考作物蒸发蒸腾量研究

Study on Reference Crop Evapotranspiration in Sichuan Province Based on Hargreaves Formula

参考作物蒸发蒸腾量是影响作物需水量的关键因素,对农业生产、灌溉指导等具有重要意义。利用四川省内11个国家级地面气象站点1991-2010年逐日气象观测数据,探讨基于Hargreaves的四川省蒸发蒸腾量估算方法。以Penman-Moanteith公式为标准对Hargreaves公式计算结果进行拟合,获取线性修正参数,并对修正后的Hargreaves公式进行验证,分析修正前后相对误差,运用Arc GIS探讨参考作物蒸发蒸腾量及修正参数的四川省内空间分布规律。结果表明利用线性拟合获得的修正参数可有效减小相对误差,四川省内蒸发蒸腾量自西向东在空间上呈现递减趋势。修正后的Hargreaves公式可反映参考作物蒸发蒸腾量实际状况,为作物需水量、农业水资源利用及农田灌溉提供理论指导。

Reference crop evapotranspiration was a key factor to estimate crop water requirement and determine agricultural production and farming irrigation. An estimation method of evapotranspiration based on the Hargreaves formula was discussed in the paper with daily meteoro- logical data of 11 national meteorology sites from 1991 to 2010 in Sichuan province. The evapotranspiration rate calculated by the Hargreaves formula was calibrated to the rate calculated by the Penman-Monteith formula which was regarded as the standard calculation. The correction parameters of Hargreaves formula was gained and verified by discussing the relative errors of the corrected Hargreaves formula. ArcGIS was used to investigate the spatial distribution of reference crop evapotranspiration and correction parameters. The results showed that the relative errors of estimation of evapotranspiration were reduced effectively by the correction parameters a and b. Based on the calculation, the evapotranspiration rate decreased gradually from west to east in Sichuan. It was concluded that the corrected Hargreaves formula reflected the actual reference crop evapotranspiration appropriately, providing the theoretical guidance for crop water demand, water resources management and irrigation.