基于修正的Gash模型模拟小兴安岭原始红松林降雨截留过程

原始红松林是我国小兴安岭地区的顶级植物群落,理解它的降雨截留过程,对区域生态、水文环境具有重要意义.采用定位研究法,于2010-2011年21场降雨数据对原始红松林的降雨截留和分配效应进行系统研究,并结合当地的气象和林分资料,利用修正的Gash模型对小兴安岭原始红松林进行林冠截留模拟.该模型对穿透雨、树干茎流、截留量的模拟值分别为:370.91、16.14、130.07 mm.穿透雨模拟值比实测值低2.28 mm,相对误差1.75％,树干茎流模拟值高于实测值8.12 mm,相对误差50.3％,林冠截留量模拟值比实测值低2.35 mm,相对误差为1.81％.穿透雨和林冠截留量的模拟值和实测值有较好的一致性,树干茎流的模拟值和实测值相差较大.综合结果表明:修正的Gash模型对小兴安岭地区原始红松林降雨截留拟合具有很好的适用性.

Simulation of rainfall interception process of primary korean pine forest in Xiaoxing'an Mountains by using the modified Gash model

Primary Korean pine (Pinus koraiensis) forest is climax community of Xiaoxing''an Mountains, in northeast of China. It has significant influence on regional ecology and hydrological environment. In order to investigate the canopy interception and allocation and evaluate forest hydrological function and benefit of virgin Korean pine forest quantitatively, positioning experiments were implemented during two rainy seasons of from 2010 to 2011 in Liangshui national nature reserve. Throughfall, stemflow and precipitation were measured and interception loss was subsequently calculated. On the basis of the observations of 21 rainfall events which collected from local weather station and forest stand respectively, we stimulated canopy interception process of virgin Korean pine forest in the Xiaoxing''an Mountains using the modified Gash model. The mesured values of total preciptation, througfall, stemflow, and canopy interception loss in virgin Korean pine forest of Xiaoxing''an Mountains were 514.1 mm, 373.19 mm, 8.02 mm, and 132.43 mm, respectively, during the study period. Throughfall and stemflow were all significantly positively correlated with precipitation (P<0.01). The simulated values of throughfall, stemflow, and interception loss by modified Gash model were 370.91 mm, 16.14 mm, and 130.07 mm respectively. Simulation value of throughfall was 2.28 mm lower than the actual value, with a relative error of 1.75%, while simulation value of stemflow was 8.12 mm higher than the measured value, with a relative error of 50.3%. The simulated value of canopy interception loss was 2.35 mm lower than the actual value, with a relative error of 1.81%. The stimulated values of throughfall and canopy interception corresponded well with measured values, while for stemflow, the simulated value was of great difference from measured value. Our findings reveal the Gash analytic model can be well applied to estimation of canopy interception loss of virgin Korean pine forest during rainy seasons in the Xiaoxing''an Mountains.