林冠截留模型

PREDICTIVE MODELS OF FOREST CANOPY INTERCEPTION

对林冠截留的研究已有近百年的历史。1971年,Rutter等人就推导出了一个具有清楚物理意义的林冠截留模型,结束了以往的林冠截留模型中只有统计模型的历史。1987年,刘家冈用数理方法,对林冠截留的时空演变过程作了很好的描述。但使用他们的模型对林冠截留进行估计时,需要同时对其它多个气象因子进行测定,而且人们普遍关心的不是林冠对次降雨截留的大小,而是林冠对降水的年截留量大小。 1979年,Gash用分析法代替了Rutter模型中的数值法,建立了截留模型,该模型能在只有降雨数据的情况下,对林冠的季节截留进行估计,结果与实测值接近。该模型将林冠截留分成两部分,即树冠截留和树干截留,因而引进了较多的参数。本文从林冠截留的过程出发,推导出一个有清楚物理意义,且含林冠和降雨参数较少的截留模型。

Based on interception process of forest canopy to rainfall, this paper derived a series of predictive interception models, including theoretical models, rainfall models, and seasonal models. Impact of last rainfall event on current interception loss was considered in these models. The concept of 'interception per unit canopy area' was introduced, which might be helpful to compare interception abilities of different tree species, different developmental stages of one species, or the same stage/species in different climate conditions. At the end of this paper, the seasonal model has been tested with the data observed in plantations of Pinus tabulaeformis in Hebei province, northern China, and the calculated values fit quite well with the observed date.