黑河上游天涝池流域草地蒸散发模拟及其敏感性分析

根据野外气象站观测资料,利用Penman、FAO-Penman、FAO-Penman-Monteith、Priestley-Taylor和FAO-Radiation等5个蒸散发模型模拟黑河上游天老池流域草地日尺度和小时尺度的蒸散发,对模拟值与观测值进行了比较,并进行了相关变量的敏感性分析。结果表明:在日尺度上, FAO-Penman-Monteith模型的模拟效果最好,FAO-Radiation模拟效果最差,其余3种模型的模拟效果较好;在小时尺度上,Priestley-Taylor模型的模拟效果最好,其余模型都不适合该地区草地小时尺度的潜在蒸散发模拟。模型输入参数对蒸散发模拟效果影响强弱顺序为辐射>气压>相对湿度>气温>风速。当地表辐射变动±10%时,模拟值变化幅度20%左右;在其他参数变动±10%时,模拟值变化幅度在8%以下,说明辐射以外的参数是模型模拟较不敏感因素。

Evapotranspiration Simulation of the Grassland and Sensitivity Analysis in Tianlaochi Catchment in the Upper Reaches of Heihe River

Tianlaochi catchment in the upper reaches of Heihe River was selected as a study area. The study object was subalpine grassland. According to the observation date of the outdoor weather station, five evapotranspiration models such as Penman, FAO-Penman, FAO-Penman-Monteith, Priestley-Taylor, and FAO-Radiation were used to simulate the daily and hourly evapotranspiration. Comparing the simulated values with the observed values, we selected the best model in the study area. In addition, we made the sensitivity analysis of relevant parameters. From the study, the results show that FAO-Penman-Monteith model is the best on day scale, and other three models (i.e., Penman, FAO-Penman, and Priestley-Taylor) are also good, FAO-Radiation model is bad; Priestley-Taylor model is the best one on hour scale, other four models are not suitable for estimating hourly evapotranspiration in the grassland of the study area, the order of the input parameters significantly influencing evapotranspiration is radiation>air pressure>air humidity>air temperature>wind speed. When the radiation changes 10%, the simulation values change about 20% and when other parameters change 10%, the simulation values change less than 8%. Therefore, the radiation is the most sensitive factor.