西双版纳热带季雨林通量分配及能量平衡问题北大核心CSCD

为了探讨我国西双版纳热带季雨林的能量分配和平衡问题,利用涡度相关系统和常规气象仪器的连续监测结果,分析了不同季节的能量通量特征和闭合特点。结果表明,西双版纳热带季雨林全年的净辐射、潜热通量、显热通量、土壤热通量和热储存量分别是4546.07、2453.24、492.22、-10.47和45.93 MJ/m^(2),土壤为热源,潜热年总值占净辐射的54.0%,显热占10.8%,能量以蒸发散为主要的耗损形式。辐射和能量有明显的日变化和季节动态,各能量分量的日变化几乎都呈白天高夜间低的单峰趋势,反照率整体为0.10~0.12,波动不大;波文比季节差异明显,为0~0.8。热带季雨林的全年闭合度为0.67,未考虑热储量时,闭合度为0.51~0.79,考虑热储量为0.53~0.80。可见,在林冠茂密的热带季雨林中,热储量对能量闭合度的贡献不大,忽略热储量并不是导致能量不闭合的主要原因。

Studies on the Flux Distribution and Energy Closure in Xishuangbanna Tropical Seasonal Rainforest, China

In order to explore the energy distribution and energy balance closure of the tropical seasonal rainforest in Xishuangbanna, China, the energy flux characteristics and closure features in different seasons were analyzed by using the continuous monitoring results of the eddy covariance system and conventional meteorological instruments. The results showed that the annual net radiation, latent heat flux, sensible heat flux, soil heat flux and heat storage were 4 546.07, 2 453.24, 492.22, -10.47 and 45.93 MJ/m², respectively. It was suggested that soil was a heat source. The latent and sensible heat fluxes were accounted for 54.0% and 10.8% of the net radiation, respectively. The main form of energy dissipation was evapotranspiration. There was obvious diurnal variation and seasonal dynamics in radiation and energy, and the diurnal variation of each energy components almost showed a unimodal trend of high daytime and low nighttime. The overall albedo ranged from 0.10 to 0.12, with a little fluctuation, and the seasonal variation of the Bowen ratio was significant, fluctuating from 0 to 0.8 throughout the year. The annual closure of tropical seasonal rainforest was 0.67, which varied from 0.51 to 0.79 when the heat storage was not considered, and from 0.53 to 0.80 when the heat storage was taken into account. Therefore, the contribution of heat storage to energy closure was small in tropical seasonal rainforest with dense forest canopies, and neglecting heat storage was not the main cause for energy non-closure.