新疆塔里木盆地绿洲区ET_0计算参数空间变化研究

A Study on Spatial Variation of ET_0 Calculation Parameters in The Oasis Area of Tarim Basin of Xinjiang

为提高Hargreaves公式在不同地区的适用性和准确性,改善区域作物需水量的估算精度和灌区灌溉管理水平。基于新疆塔里木盆地绿洲区5个典型气象站1961-2014年逐日气象资料,以最高温度、最低温度、大气顶太阳辐射为自变量,以Penman-Monteith公式计算的ET_0为因变量,对Hargreaves模型参数进行拟合与分析。结果表明:研究区全年和夏季转换系数K变化趋势相同,均从研究区北向南逐渐增大,春、秋、冬季变化趋势则相反;全年和夏季指数系数n变化趋势相同,也均从研究区的南向北递增,春、秋、冬季则从北向南逐渐增加;温度偏移量Toff总体表现为从南向北逐渐增加。率定后的Hargreaves公式与P-M公式的相关指数,全年最大,为0.787,春秋次之,分别为0.704和0.722,冬季最小,为0.454,拟合后的参数标准误表明拟合值全年最准确,冬季最差。

In order to enhance the applicability and accuracy of Hargreaves equation in different regions and improve the regional crop water content estimation accuracy and the Irrigation District management level,based on the daily meteorological data of the five meteorological stations in Tarim basin oasis area from 1961 to 2014,this paper analyzed the Hargreaves model parameters by taking the maximum temperature,minimum temperature,atmospheric top sun radiation as the independent variable,and the ET_0 value calculated by the penman Monteith formula as dependent variable. The results show that the variation trend of year-round and summer conversion coefficient K of the study area is the same,which gradually increase from the north to the south,while the trend in spring,autumn and winter is the opposite; annual and summer index coefficient n have the same change trend,which gradually increase from the south to north,while gradually increase from the north to the south inspring,autumn,winter; the temperature offset Toffoverall gradually increase from the south to the north. For the calibrated related index of Hargreaves formula and P-M equation,the annual value is the maximum as 0. 787,followed by that in spring and autumn,as 0. 704 and 0. 722,respectively,the value in winter is the minimum as 0. 454. The fitting parameters standard error indicates that the fitting value throughout the year is the most accurate while the value in winter is the lowest.