作 者：
Sudarshan Prasad;Vishal Kumar;Ashok Kumar Sinha;A K P Singh
关键词：
参考蒸散量;FAO-56 Penman-Monteith模型;哈格里夫斯模型
摘 要：
精确测定参考作物蒸散量(ETo)对于精确计算作物水分利用是非常必要的.FAO-56 Penman-Monteith法(FAO-56 PM)是联合国粮食和农业组织认可的测定参考作物蒸散量的标准方法.可是,一些天气变量,特别是相对湿度、太阳辐射和风速经常缺失,这可能会妨碍利用FAO-56 PM方法进行ET.估算.为了克服以上情况,评价哈格里夫斯法在估算位于拉金德拉农业大学的菩萨天文台数据的准确性和实用性是很重要的.哈格里夫斯方程经常高估一个区域,因此该方法在普萨地区已经不再使用.利用统计回归分析对哈格里夫斯系数进行校正,得到结果分别由0.002 3和17.8降到0.001 62和-3.039 39.比较利用修正的哈格里夫斯方程和FAO-56 PM计算得到ET.,均方根误差(RMSE)和均偏置误差(MBE)比最小值0.77和-0.11 mm/d小1.00和0.21,相应的导致在ET.估算中出现小错误.1998-2006年间的数据经R2、X2检验和一致性指数检测均表现出显著相关性.在普萨地区,利用修正的哈格里夫斯方程(ETAHG平均值为3.71 mm/d)和FAO-56PM方法估算得到的ET.基本一致.
译 名：
Evaluation of Hargreaves Method for Estimating Reference Evapotranspiration at Pusa, India (Extracts)
摘 要：
Accurate determination of reference evapotranspiration( ET o) is very essential to precise computation of crop water use. The FAO-56 Penman-Monteith method( FAO-56 PM) is the standard method recognized by the Food and Agriculture Organization of the United Nations for estimating reference evapotranspiration. Unfortunately,some of the weather variables,especially relative humidity,solar radiation,and wind speed are often missing,which could impede the estimation of ET o with the FAO-56 PM method. To overcome the availability of climatic variables,assessing the accuracy and usefulness of Hargreaves method for Pusa Observatory located in the campus of Rajendra Agricultural University,Pusa is important.The Hargreaves equation showed a regular overestimation of the region,hence the method was discarded for Pusa location.Modifications were made in Hargreaves coefficient using statistical regression analysis and were calibrated from 0. 002 3 and 17. 8(Hargreaves equation) to 0. 001 62 and-3. 039 39 respectively. Both the Root Mean Square Error(RMSE) and the Mean Bias Error( MBE) of the comparison between ET o computed by adjusted Hargreaves equation and that computed from FAO-56PM method were less than 1. 00 and 0. 21 with a minimum of 0. 77 and- 0. 11 mmd,respectively leading to small errors in the ET o estimates. R2,X2-test,and index of agreement values confirmed strong relationships among data for the year from 1998 to2006. It indicated that ET o computed by adjusted Hargreaves equation( an average value of ET AHG3. 71 mmd) and that computed from FAO-56 PM method were in close agreement at Pusa region.
