AWRA-L模型估算区域林冠降雨截留量

目前模拟林冠截留的Gash模型的应用多是针对某一特定点或特定林分开展,而在区域范围内的应用国内尚无报道,在国外也仅见其在澳大利亚水资源评价系统AWRA.L模型中的应用。该研究介绍了AWRA-L(Australian water resources assessment-landscape)模型,并利用GI_。ASS LAI遥感数据结合浸水法获得的林冠持水量,使用该模型对试验点白桦(Betula platyphylla Suk.)天然次生林2013年的林冠截留进行模拟。结果显示,基于Van等改进过的Gash模型的AWRA.L模型和基于Gash(1979)模型的AWRA—L(1979)模型,对累积林冠截留模拟的绝对误差分别为-4.4和1.5 mm,相对误差分别为-8.7%和3.0%;对于单场降雨林冠截留的模拟结果显示,2模型的模拟误差值分别为(-0.15±1.64)和(-0.03±1.39)mm,模拟值与实测值之间无显著差异。研究结果说明结合GLASS LAI遥感数据,AWRA-L模型可以应用于区域范围林冠截留的模拟,模拟结果较好。

AWRA-L model for simulating interception of rainfall loss in large scale

Abstract: The application of the Gash model to simulate canopy interception is mostly on the study plot or a specified forest, and the application in a landscape scale is only reported in the Australian Water Resource Assessment system (AWRA-L). This study introduced the AWRA-L model, and aimed to simulate the interception loss of the natural secondary forest of birch (Betula platyphylla Suk.) during 2013 in China. The GLASS LAI data and submerging method were used to get the canopy capacity for different periods. The leaf area index (LAI) value obtained before germination was assumed to be the area of branches and trunks. While the LAI value obtained after germination was the area of the leaves, branches and trunks. The differences between the LAI values after and before germination were the area of leaves when the growing of branches and trunks was ignored. The submerging method showed that the water capacity of leaves and stems per unit area were 0.17 and 0.33 mm, respectively. The capacity of branches and trunks was 0.23 mm. The capacity of leaves was 0.04-0.51 mm. The mean canopy capacity was 0.60±0.14 mm. The intercept method showed the canopy capacity and the trunk capacity were 0.62 and 0.04 mm, respectively. The whole capacity of the birch forest in its over ground parts was 0.66 mm. The canopy capacity by the submerging method and the intercept method was not significantly different (P=0.23). Considering of the high canopy cover fraction of the birch forest, both the simulating results of AWRA-L model based on Van model and the AWRA-L(1979) model based on Gash (1979) model were discussed in the paper. For the 25 rain events measured during the experiment, the simulating errors of the cumulative interception loss obtained from the AWRA-L model and the AWRA-L(1979) model were -9.2 and -1.7 mm, respectively. The relative errors were -14.8% and -2.8%, respectively. Both the AWRA-L model and the AWRA-L(1979) model underestimated the interception loss. When the rain event on June 8 with the biggest simulating error was eliminated, the cumulative simulating errors of the AWRA-L model and the AWRA-L(1979) model were -4.4 and 1.5 mm, respectively. The relative errors were -8.7% and 3.0%, respectively. The mean errors of the simulating interception loss for single rain event by these two models were -0.15 and -0.03 mm, respectively. The simulating value and measured was not significantly different. The results illustrated that the canopy capacity obtained by the data of GLASS LAI and submerging method could be used to determine the canopy capacity and the results could be used for simulating of interception loss by the AWRA-L model. The AWRA-L model is reliable to simulate both the cumulative interception loss for a long period and the interception loss for a single rain event in a landscape scale.