基于气温的潜在蒸散发量估算方法在我国西北干旱地区的应用比较

Comparison of temperature-based methods for estimating potential evapotranspiration in the arid region of Northwest China

根据石羊河流域两个气象站的历史数据,选取7种基于气温的潜在蒸散发量估算方法,以FAO56-PM法计算的ET作为参考值,对其进行比较分析,最后再用实测蒸发皿蒸发量对这些方法在西北干旱地区的适用性进行评价。结果表明:在两个站使用7种方法的初始参数时,多数产生较大误差。校正参数后两个站所有方法在估算逐月ET和月平均ET时都得到明显改进。改进的Romanenko法在两个站所有月份以及全年误差都最小,其次是Hargreaves和Linacre法。用实测小型蒸发皿蒸发量进行验证时,改进的Romanenko法与其相关系数最高,为0.97,其次是Linacre和Hargreaves法。就气温法而言,校正参数后的Romanenko,Hargreav-es和Linacre法可在此研究区域用于估算ET,并建议优先选择Romanenko法,与小型蒸发皿的折算系数适宜选取0.60。

Seven temperature- based methods （Thornthwaite, Linacre, Blaney- Criddle, Kharrufa, Hargreaves, Hamon and Romanenko） for estimating potential evapotranspiration were compared and analysized with the FAO56 -PM method at two meteorological stations in the Shiyang River basin in China. Seven temperature - based methods compared with the pan evaporation in the arid region Northwest China. The results showed that when the original parameters were used, larger biases existed for the most of the methods at two stations. When using calibrating parameters, all methods have been obviously improved in estimating monthly ET. The modified Romanenko method produced the smallest error during all months at two stations, followed by the Hargreaves, Linacre and Blaney- Criddle methods. When verified by pan evaporation, Romanenko method had the greatest correlation coefficient, 0.97, followed by the Linacre, Hargreaves and Blaney - Criddle methods. The Romanenko, Hargreaves, Linacre and Blaney -Criddle methods can be used for estimating ET in the study region as far as the temperature -based methods are concerned, when using calibrating parameters. The Romanenko method and a conversion coefficient of 0.60 for the pan should be selected preferably.