我国亚热带毛竹林生长季能量通量过程及闭合度分析

为探讨我国亚热带毛竹林(Phyllostachys edulis)生长季的能量平衡关系,利用开路涡度相关法,对2011年毛竹林生长季的能量通量的变化特征进行了研究,并应用能量平衡比率法和线性回归2种方法,分析了能量闭合的特点。结果表明,我国亚热带毛竹林生长季的净辐射总量为1738.2 MJ m–2,显热通量为354.3 MJ m–2,潜热通量为1146.0 MJ m–2,土壤热通量为58.9 MJ m–2,土壤为热汇,显热通量占净辐射的20.4%,潜热通量占65.9%,土壤热通量占3.4%。毛竹林生长季的能量闭合度为0.89,月平均闭合度为0.91,但仍有11%的能量不闭合。可见,毛竹林生长季以潜热能量散失形式为主,各能量分量均以净辐射变化为基础,且日变化基本呈单峰型曲线。

Energy Flux and Energy Balance Closure Analysis of Phyllostachys edulis Forest in Subtropical China during Growing Season

In order to understand the energy balance closure of Phyllostachys edulis forest in subtropical China during growing season, the changes in energy flux of P. edulis forest were studied from April to September in 2011 by using open-path eddy covariance method, and the characteristics of energy closure were analyzed by using EBR (Energy balance ratio) and OLR (Ordinary linear regression). The results showed that total net radiation of the forest in growing season was 1738.2 MJ m^-2, and the sensible flux heat, latent heat flux, and soil heat flux were 354.3 MJ m^-2, 1146.0 MJ m^-2, and 58.9 MJ m^-2, respectively. It was suggested that soil was a heat sink. The sensible and latent heat fluxes were accounting for 20.4% and 65.9% of the net radiation, respectively. The enrgy balance closure of P. edulis forest in growing season was 0.89, and the monthly average was 0.91, but there was 11% of energy imclosure. Therefore, the latent heat flux was the main form of energy loss. Diurnal variation in energy components all showed single peak curves based on net radiation, and energy closure was at high level.