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选择Gash(1995)改进后的模型对祁连山东部青海云杉林冠层截留进行模拟。首先在2009年的5月底至9月期间对降水事件、降水截留和林冠结构进行观测,其次对林冠附加截留量进行计算,在不同的时间步长上利用Gash模型模拟截留量,最后对模型参数进行敏感性分析。结果表明:Gash模型对整个观测期间林冠截留模拟值比实测林冠总截留量偏低8.70%,15 d尺度和次降雨事件尺度上模拟值比观测值分别偏低18.92%和14.23%;附加截留占总截留的74.94%,吸附截留占总截留的25.06%;饱和林冠的平均蒸发强度和降雨强度的比值是模型的敏感性参数,精确获得平均蒸发强度是保证模型精度的前提条件,并且独立降水事件的界定是提高Gash模型的关键点。
The improved model of Gash (1995) was chosen to simulate the canopy interception of Picea crassifolia forests in eastern Qilian Mountains. First, the precipitation events, precipitation interception and canopy structure were observed from the end of May to the end of September 2009, followed by the calculation of the additional interception of the canopy, the Gash model was used to simulate the interception at different time steps, and the model parameters Conduct a sensitivity analysis. The results showed that the simulated values of canopy interception of Gash model were 8.70% lower than those of the measured canopy during the whole observation period, and the simulated values were 18.92% and 14.23% lower than the observed values on the 15-day scale and the sub-rainfall event respectively. The total interception of 74.94% and the retention of interception accounted for 25.06% of total interception. The ratio of average evaporation intensity and rainfall intensity of saturated canopy is the sensitivity parameter of the model. Accurately obtaining the average evaporation intensity is the prerequisite for ensuring model accuracy. The definition of Gash model is to improve the key points.