GCM预测模式下黑河流域潜在蒸散发的演变分析

以Penman-Monteith模型为基准，通过参数修正从7个温度类模型中优选出适用于黑河流域潜在蒸散发（PET）估算的最优模型，再根据CMIP5中CSIRO-Mk3.6.0气候模式输出的研究区未来气候情景数据，对黑河流域历史时期（1961—2015年）和未来2021—2050年（T1）、 2051—2080年（T2）2个时段的PET值进行估算，并从时间和空间尺度2个方面分析其变化特征. 结果表明:1）研究区气象数据资料缺乏时（例如仅有气温数据），参数修正后的Hargreaves-Samani模型可以作为Penman-Monteith的替代模型；2）黑河流域历史时期多年平均PET为1 102 mm，空间上由上游向下游逐渐增加，与多年平均气温的空间分布具有较强的一致性；3）流域未来多年平均PET空间分布特征基本不变. 受流域未来最高、最低气温增加的影响，流域多年平均PET在T1和T2时段较历史时期分别增加15%和20%. 不同空间位置处，PET变化存在差异:T1时段中游酒泉站较历史时期有所下降，而其余站点则有所上升，T2时段所有站点较历史时期则均有上升；且未来2个时段流域上游PET增幅均大于流域下游，这种空间差异性与流域未来最高、最低气温变幅的空间差异性较为一致. 

Analysis of potential evapotranspiration in Heihe River Basin by GCM

Out of seven temperature-based potential evapotranspiration (PET) models, the Penman-Monteith model was selected for parameter correction in the Heihe River Basin. From climate output of CSIRO-Mk3.6.0, PET values were estimated for 1961-2015, 2021-2050 (T1) and 2051-2080 (T2), temporal and spatial variations were then analyzed. Hargreaves-Samani model with adjusted parameter value can be used in place of Penman-Monteith when meteorological data of the basin was absent (such as when temperature data only are available). Average PET was found to be 1 102 mm from 1960 to 2015, which increased from south (upstream) to north (downstream). Spatial distribution of average PET was unchanged in future periods, with PET reaches 1 622mm in T1, and 1 675mm in T2 period, 15% and 20% higher than historical period. Differences in PET changes were found among stations. Jiuquan station in the middle reach and Ejinaqi station in the lower reach decreased by 1.5% and 0.05% respectively; other stations increased by 1.4% - 20.9% for T1 period. For T2 period, all stations increased by 2.6% - 28.2%. The increases in PET in upper reach were greater than in lower reach for the two future periods.