亚热带毛竹林生态系统能量通量及平衡分析

利用开路涡度相关系统和常规气象观测仪器,对亚热带(浙江省)毛竹林生态系统2011年的净辐射、显热通量、潜热通量、土壤热通量以及气温、地温、降雨量等气象要素进行了连续观测,定量分析了毛竹林生态系统能量通量的变化和各能量分量的分配特征,并计算了能量闭合度以及波文比。结果表明:毛竹林全年净辐射为2628.00 MJ/m2,显热通量为576.80 MJ/m2,潜热通量为1666.77 MJ/m2,土壤热通量为-7.52 MJ/m2,土壤为热源,各能量分量季节变化明显,日变化基本呈单峰型曲线变化。显热通量占净辐射的22.0%,潜热通量占63.4%,毛竹林生态系统潜热通量为能量散失的主要形式。波文比逐月变化规律不明显,波动较大,在0.07—1.77之间变化,能量平衡比率法得出毛竹林年能量闭合度为0.85,月平均闭合度为0.84,能量闭合度高于线性回归法计算结果,但仍有15%的能量不闭合。

Energy flux and balance analysis of Phyllostachys edulis forest ecosystem in subtropical China

The atmospheric boundary layer is a passage between the atmosphere and the land surface, through the atmospheric momentum, energy and substances are transported upwards and downwards in two layers on earth surface.In the lower atmospheric planetary boundary layer turbulent transport is important connection for substance and energy exchange between the atmosphere and the earth surface, currently it is one focus of earth system science. By using open-path eddy covariance system and micro-climate instruments, the net radiation, sensitive heat flux, latent heat flux, soil heat flux, air temperature, soil temperature, and precipitation were conducted in Mao bamboo forest ecosystem of subtropical in China since 2011. But the energy flux and analysis of Mao bamboo forest ecosystem reported in the literature at home and abroad is very few, in subtropical regions to establish long-term continuous observation of the flux tower, enhancing the research is highly requirement. The diurnal and monthly variation of energy balance as well as the distribution pattern of each component were analyzed, and energy closure and Bowen ratio also were calculated. As an important index to evaluate the reliability of eddy covariance measurements, energy balance analysis has been widely accepted by the community. Using two methods of OLR(Ordinary least spuares) and EBR(Energy balance ratio), energy imbalance characteristics of the Mao bamboo forest ecosystem were systematically analyzed compared in the paper. The results showed that: the yearly net radiation of the Mao bamboo forest ecosystem was 2628.00 MJ/m², and the sensitive flux heat, latent heat flux, and soil heat flux were 576.80 MJ/m², 1666.77 MJ/m², and -7.52 MJ/m², respectively. The results suggest that soil of Mao bamboo forest was a heat source. The energy balance components had obvious seasonal pattern, diurnal variations of energy balance components existed on expected single peaks. The sensible and latent heat fluxes almost have 22.0% and 63.4% of the net radiation, respectively, indicating that latent heat flux was the main form of energy loss in this forest ecosystem. Monthly variation of the Bowen ratio is slight, and fluctuated from 0.07 to 1.77, the yearly enrgy balance closure of the Mao bamboo forest ecosystem was 0.85, and the mean monthly averge was 0.84, yet energy imclosure of 15% still existed for the energy balance of Mao bamboo forest ecosystem.