陆面潜在蒸散计算模型在甘肃省黄土高原的适用性研究

Adaptability of Potential Evapotranspiration Estimation Models in the Loess Plateau of Gansu Province

甘肃省黄土高原地区处于半干旱半湿润气候过渡区,潜在蒸散的准确估算是该区水资源评估的重要工作之一。运用西峰国家基准气候站1961—2006年气象资料,选用5种半干旱地区研究潜在蒸散普遍适宜的计算模型,以该区的蒸发量为参考,对各种计算模型进行了评估。结果表明,FAO Penman—Monteith(1998)模型与蒸发量相关性显著,均方差值小,稳定性高,是计算该地潜在蒸散的首选模型;其次为FAO PPP—17模型;Hargreaves模型所需气候因子较少,计算便捷,准确性较好,有一定使用优势;Priestley—Taylor模型计算值有一定参考意义,但在夏季与蒸发量的相关水平较低,在使用时还要作进一步地订正;24 Radiation模型的夏季计算值与蒸发量的相关性不能通过假设检验,有一定的时间局限性,不宜作为该地区研究潜在蒸散的计算模型。

The Loess Plateau of Gansu Province is located in semi-arid and semi-humid transition zone. The accurate estimation of potential evapotranspiration is one of the main works in assessment of water resources. Based on the meteorological data at Xifeng National Base Climate Station in 1961--2006, 5 kinds of model for calculating potential evapotranspiration widely used in semi-arid area are chosen for the evaluation with reference of evaporation. The FAO Penman--Monteith （1998） model has a significant relevance, small standard deviation with evaporation, and the high stability and is the most suitable model for calculating the potential evapotranspiration. The next suitable model is the FAO PPP--17 model. The Hargreaves model has the ad- vantages of fewer climatic factors, convenient use, and higher accuracy over other models in estimating potential evapotranspiration. It is demonstrated that the Priestley--Taylor model has some reference values in calculating evapotranspiration, but the model shows a low relevance level with evaporation. Therefore, the model should be modified before it is put into use. The association between calculated value of the 24Radiation model and evaporation dose not reach the level of assumption checking in summer and thus its use is limited. The model should not be used in research work in the Loess Plateau of Gansu province.