修正Gash模型在兴安落叶松天然林林冠截留中的应用

为验证修正Gash模型在大兴安岭地区兴安落叶松天然林中的适用性,基于2014年4—10月56场降雨,评价兴安落叶松林冠对次降雨、周累积降雨、季节降雨及年降雨截留量的模拟效果。结果表明:观测期内总降雨量为(289.4±1.66)mm,穿透雨量、树干茎流量和林冠截留量分别占同期降雨总量的75.44%、2.60%和21.95%。林冠截留量的模拟值与实测值分别为65.17 mm和63.53 mm,相对误差为2.58%;周累计林冠截留量与实测值的相对误差为2.59%;春、夏、秋季模拟值与实测值相对误差分别为0.71%、3.62%和0.44%。单次降雨林冠截留量只有在降雨量较小情况下,模拟精度较高;当降雨量增加到12.23 mm时,模拟精度显著降低。据此表明,修正Gash模型对兴安落叶松天然林林冠截留总量的模拟具有较好的适用性,可为研究该地区森林水分循环和利用提供科学简便的方法。

Simulation of canopy rainfall interception of the Larix gmelinii forest by the modified Gash model in Greater Hinggan Mountains

In order to verify the applicability of the modified Gash model in simulating canopy rainfall interception of nat?ural Larix gmelinii forest in Greater Higgnan Mountains, fifty?six rainfall data of canopy interception, meteorological fac?tors and stand characteristic from April to October 2014 were analyzed and compared with the simulation in terms of weekly cumulative rainfall, seasonal cumulative rainfall and annual rainfall. The experiment and simulation results showed that, during the observation period, the rainfall was amounted to (289.4±1.66) mm, in which the through?fall, stem?flow and canopy interception were measured as 75.44%, 2.60% and 21.95% of the total rainfall, respectively. The simulated value of overall canopy interception was 65.17 mm and the measured one was 63.53 mm, counting a 2.58%relative error between them. The relative error between the simulation and measurement of the weekly cumulative canopy interception was 2.59%. When the seasonal factor was taken into account, the relative errors between them were 0.71%, 3.62% and 0.44% for spring, summer and autumn, respectively. The lower value of precipitation of a single rainfall cor?responded to the higher simulation accuracy of the canopy interception. When the precipitation of a single rainfall in?creased to a higher value, e.g. 12.23 mm, the simulation accuracy was significantly compromised. In general, this modi?fied Gash model can predict canopy interception in the natural L. gmelinii forest and thus provide a scientific and simpli?fied method for the future research and management of hydrological cycle in Greater Hinggan Mountains.