祁连山中部亚高山草地作物系数估算

利用Lysimeter蒸散仪于2011-2014年对祁连山中部黑河上游天涝池流域亚高山草地实际蒸散量进行观测。用FAO Penman-Monteith模型对草地参考蒸散量进行估算，根据草地植被高度结合气象数据，以估算日尺度作物系数，以估算的作物系数与模拟的参考蒸散量计算草地实际蒸散量，并用观测值进行验证。结果表明：FAO改进后的作物系数计算方法适合该区域草地作物系数的计算；以FAO Penman-Monteith模型估算的日蒸散量为0.50~7.26 mm，生长季日均蒸散量有年际变化，2011年 > 2014年 > 2012年 > 2013年。总体来看，土壤蒸发总量年际变化不大，影响蒸散量年际变化的主要部分是植被的蒸腾。

Grass Crop Coefficient Based on the Estimated Evapotranspiration at the Subalpine Meadow of the Qilian Mountains

Tianlaochi catchment is located in the upper reaches of the Heihe River Basin. Evapotranspiration of subalpine meadow was observed by micro-lysimeter from 2011 to 2014. Reference evapotranspiration (ET₀) of the grass was estimated using the FAO Penman-Monteith model. The daily crop coefficients were calculated by the improved crop coefficient formula in relation to the weather data and the height of the grass., The actual evapotranspiration was calculated by the estimated crop coefficient and reference evapotranspiration, which was tested by the observed evapotranspiration. The results show that the improved crop coefficient formula recommended by FAO is suitable to be used in the study area, the daily ET₀ estimated by, FAO Penman-Monteith model ranges from 0.50 to 7.26 mm·d^-1, the ET₀ has inter-annual difference and the sequence of ET₀ in the study period is 2011, 2014, 2012, 2013. From measurement data, we find soil evaporation having a little inter-annual change, that means the transpiration of grass is a key component to control inter-annual different of ET₀. From the study, we can draw a conclusion that the actual evapotranspiration of grass in the subalpine meadow can be estimated by crop coefficients and reference evapotranspiration, both depending on weather data which are easily obtained by automatic weather station.