Hargreaves公式在塔克拉玛干沙漠腹地的适用性

对运用Hargreaves公式计算参考作物蒸散量(ET0)在干旱区的适用性存在不同观点.为了求证Hargreaves公式在极端干旱区塔克拉玛干沙漠腹地的适用性,利用2005-2010年塔克拉玛干沙漠研究站的气象资料,以利用Penman-Monteith公式计算的结果为标准,对利用Hargreaves公式计算的ET0进行了对比分析,并对两种计算结果差异的成因进行了阐释.结果表明:在年时间尺度上,利用Hargreaves公式计算的结果略大于利用Penman-Monteith公式计算的结果,标准差介于32.86～35.00 mm,年参考作物蒸散量计算结果呈现弱变异程度；在月时间尺度上,用两种方法计算的参考作物蒸散量呈现中等变异程度,蒸散量绝对偏差介于-3.26～8.73 mm,相对偏差介于-12.20％～29.02％,除了10月与11月,其余月份相对偏差均保持在10％之内.用两种方法计算的10月与11月份ET0产生差异的最主要原因在于有较高的温度较差.最后,经过对年、月参考作物蒸散量进行t-检验及建立回归方程,表明Hargreaves公式适用于极端干旱的塔克拉玛干沙漠腹地.

Applicability of the Hargraeves Method in Estimating Reference Evapotranspiration in the Taklamakan Desert Hinterland

There are different opinions on the applicability of the Hargreaves method in calculating reference crop evapotranspiration (ET0) in arid land. In order to test the applicability of the Hargreaves method in the Taklamakan Desert hinterland, we carried out the current study using the metadata in 2005-2010 collected at the meteorological station in the Taklamakan Desert hinterland. The Penman-Monteith method was set as standard to compare the difference between the two methods. The results showed that at annual scale, the ET0 calculated with the Hargreaves equation was a little higher than that obtained by Penman-Monteith method, the standard deviation were 32.86~35.00 mm, and the annual reference crop evapotranspiration (ET0) presented weak variation; at monthly scale, the reference crop evapotranspiration (ET0) presented a middle variation, the absolute deviation of monthly ET0  was -3.26~8.73 mm between the two methods, and the monthly relative deviation was -12.20%~29.02%, and the ET0 deviations were all not more than 10% except for October and November. It was documented that the difference for the calculating ET0 between the two methods was resulted from the higher temperature range. Based on the estimated ET0 at annual and monthly scales by the two methods, our results indicated that the ET0  calculated with the Hargreaves method was applicable in the extreme arid area of the Taklamakan Desert hinterland.