双波长交互法测算华北人工林平均水热通量的应用分析

Application of Two-wavelength Bichromatic Correlation Method to Calculate the Average Surface Energy and Water Vapor Fluxes in Plantation North China

基于红外-微波闪烁仪方法(Optical-Microwave Scintillometer,OMS),对华北低丘山地人工林生态系统进行热量通量观测,并比较OMS估算结果与涡动相关系统(Eddy Covariance,EC)观测结果的差异,分析OMS方法的估算结果对能量平衡的影响,探讨影响OMS观测结果的影响因子。结果表明,OMS系统观测的显热通量与EC观测结果具有良好的一致性,但观测的潜热通量比EC观测结果高估约28%。由于对潜热通量的高估,OMS系统在观测研究中存在过闭合现象,超出幅度约5%。分析认为,波文比、风速对OMS观测影响显著。OMS作为新兴的水热通量观测方法,可以直接同时测算出区域尺度水平上显热通量和潜热通量,缩短了采样间隔,统计不确定性减小,有助于更精确地测量热量通量,深入研究能量闭合问题。

A field campaign which measuring heat fluxes based on the optical-microwave scintillometer（OMS）, was conducted in the plantation ecosystems in the hilly area of North China. The differences between the results of OMS and Eddy Covariance（EC） system were compared in details, the impact of OMS results on the energy balance was estimated, and affecting factors of OMS were also discussed. Results showed that, the sensible heat flux observed by OMS is in favorable consistency with the EC observations, while the latent heat flux estimated by the OMS system is overvalued by 28%. The energy balance observed by the OMS system was over-closed and with an excess of 5%, because of the overestimation of latent heat flux. Bowen ratio and wind speed have great influences on the OMS. As a new method for measuring surface energy and water vapor fluxes, OMS can simultaneously and directly measuring sensible heat flux and latent heat flux at the regional scale, shortening the sampling interval, reducing the statistical uncertainties, contributing to a more accurate measurement of the heat flux and benefit for the further research of the energy balance.