中文摘要：

蒸散发是水循环的重要组成部分,但高海拔山区的观测难度导致对于该区实际蒸散发以及蒸散发对山区水循环影响的认识相对缺乏.利用两个小型称量式蒸渗仪（micro-lysimeter）对黑河山区2009年7月至2010年6月的草地日蒸散发进行实地观测,结合实测结果,对FAO-56 Penman-Monteith（F-P-M）、Priestley-Taylor（P-T）和Hargreaves-Samani（H-S）3种蒸散发估算方法在山区的适用性进行分析,并讨论试验点的蒸发皿系数.结果表明：观测期间,试验点总蒸散发439.9mm,占同期降水量的96.5%,且蒸散发呈现明显的季节分配：5—10月的蒸散发为389.3mm,占全年蒸散发的88.5%.3种估算方法都能较好计算山区夏季蒸散发,且适用性顺序依次为P-T〉F-P-M〉H-S,但3种方法都不能有效估算山区冬季的蒸散发.试验点夏季日蒸发皿系数在0.7～0.8,而冬季无稳定的日蒸发皿系数.

英文摘要：

Evapotranspiration （ET） is an important component of water cycle, but its measurement in high altitude mountainous region is quite difficult, inducing the insufficient understanding on the actual ET in high altitude mountainous region and the effects of ET on this region＇ s water cycle. In this paper, two small type weighing mini-lysimeters were applied to measure the daily ET in a piece of grassland in a high altitude mountainous region of the Heihe River basin from July 1 st, 2009 to June 30th, 2010. Based on the measured data, the methods of FAO-56 Penman-Monteith （ F-P- M）, Priestley-Taylor （P-T）, and Hargreaves-Samani （H-S） were employed to estimate the ET to analyze the applicability of the three methods for the mountainous region, and the pan coefficient at the measurement spots was discussed. During the measurement period, the total annual ET at the measurement spots was 439.9 mm, accounting for 96.5% of the precipitation in the same period, and the ET showed an obvious seasonal distribution, being 389.3 mm in May-October, accounting for 88.5% of the annual value. All the three methods could be well applied to estimate the summer ET but not the winter ET, and their applicability followed the sequence of P-T 〉 F-P-M 〉 H-S. At the measurement spots, the daily pan coefficient in summer was 0.7-0.8, while that in winter was quite variable.