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能量不闭合是几乎所有地表通量观测研究中存在的问题.在能量平衡估算中,人们往往关注有效能量(感热和潜热之和)系统低于可利用能量(净辐射与土壤热通量之差)的统计结果,而忽视了有效能量大于可利用能量的“过闭合”样本存在及其对整体能量闭合率的贡献.利用2004年华北玉米生育期的观测资料,探讨了能量分量的时间同步性,认为各能量分量与净辐射的时间不同步是导致“过闭合”现象系统出现的原因.将有效能量位相提前半小时与可利用能量进行相关分析,有效减少了能量比率大于1和小于0.5的样本,提高了不同尺度的能量利用率.多种时间尺度的能量分配与转化规律分析显示,潜热在不同时间尺度上都是主要的能量消耗方式,能量闭合差随玉米的生长不断增大,长达7旬的时间超过感热,表明热量储存和光合耗能在玉米生育期能量平衡中具有重要作用.
Energy unbalance is a problem that exists in almost all the studies of surface flux observation.In the energy balance estimation, people often pay attention to the fact that the effective energy (sum of sensible heat and latent heat) is lower than the available energy (net radiation and soil heat flux But ignores the existence of “over-closed” samples whose effective energy is greater than the available energy and its contribution to the overall energy closure rate.Based on the observation data of the growth stages of maize in North China in 2004, the energy components Time synchronism, it is considered that the time synchronization between each energy component and the net radiation is the cause of the phenomenon of “over-closure” phenomenon.Analysis of correlation between available energy phase and half-hour of available energy can effectively reduce the energy ratio more than 1 and less than 0.5 to improve the energy efficiency at different scales.Analysis of energy distribution and transformation at various time scales shows that the latent heat is the main mode of energy consumption at different time scales and the difference of energy closure with the growth of maize Increasingly, up to 70 days over the sensible heat, indicating that heat storage and photosynthetic energy consumption in the corn growth period energy balance plays an important role.