应用修正的Gash解析模型对岷江上游亚高山川滇高山栎林林冠截留的模拟

Application of a revised Gash analytical model to simulate subalpine Quercus aquifolioides forest canopy interception in the upper reaches of Minjiang River

修正的Gash解析模型具有较好的物理基础,是目前估算和预测林冠截留的有效工具。基于2007年6月到9月的降雨数据、气象和林分结构资料,采用修正的Gash解析模型对岷江上游川滇高山栎林冠截留进行了模拟。结果表明,林冠持水能力为0.23mm,树干持水能力为0.041mm,树干茎流系数为0.013,使林冠饱和的降雨为0.3mm;研究期间实测的林冠截留量为80.2mm,占总降雨量的16.5%,应用模型模拟的林冠截留总量为81.8mm,高于实测值1.6mm(高于实测值2.0%),林冠截留和树干茎流周累积量模拟值均与实测值有很好的一致性,敏感性分析结果显示,应用修正的Gash解析模型进行岷江上游川滇高山栎林冠截留模拟研究中,模型最易受林冠持水能力影响,其次为郁闭度、树干持水能力,影响最小的林分参数为树干茎流系数。

Based on rainfall data,weather information and forest structure from June to September in 2007,we applied the revised Gash analytical model to simulate subalpine Quercus aquifolioides forest canopy interception in the upper reaches of Minjiang River.The results showed that the canopy storage capacity was 0.23 mm,the stem storage capacity was 0.041 mm,the stemflow partitioning coefficient was 0.013,and the amount of rainfall needed to saturate the canopy was 0.3 mm.The canopy interception was 80.2 mm during the study period,which was 16.5% of total rainfall,whereas the total interception by applying model was 81.8 mm which was higher over l.6 mm of measured value.There was a good consistency between the simulated and measured value in the weekly cumulative amount of canopy interception and stemflow.The sensitivity analysis indicated that the revised Gash analytical model was the most vulnerable to be influenced by the canopy water storage capacity,followed by canopy coverage,stem water storage capacity,and stemflow coefficient as well during the study period in the subalpine Q.aquifolioides canopy interception in the upper reaches of Minjiang River.Our result suggested that the revised Gash analytical model with a physical basis was an effective tool in estimating and budget the canopy interception in a subalpine Q.aquifolioides forest.