缙云山针阔叶混交林涡相关适用性及碳通量变化特征

目的 探讨涡度相关法在缙云山针阔叶混交林的适用性，并明晰针阔叶混交林生态系统的碳源/碳汇情况，从而为该地区的森林经营和林业可持续发展提供科学依据。 方法 利用涡度协方差观测方法，获得了缙云山针阔叶混交林2019.11—2020.10的碳通量监测数据。通过湍流数据质量评价、能量闭合及通量足迹，分析对涡度相关应用于该下垫面的适用性进行验证。在时间序列上对碳通量的变化进行分析，并对研究区内碳源或碳汇情况进行评估。 结果 研究期内，显热通量(H)、潜热通量(LE)和碳通量(Fc)的湍流数据质量评价较好，高质量数据占比分别为77%、61%和62%；在生长季(4—10月)，上层能量闭合率为0.82，下层能量闭合率为0.73；研究期内通量高贡献区域所处方向与全年主风向（东北）一致；在研究期内，该生态系统年固碳量为887.40 g·m−2，月均日变化和季节均日变化大多为双峰型，生长季的Fc累积变化量为：−826.2 g·m−2，非生长季则只有：−61.2 g·m−2；影响碳通量的主要环境因子是光合有效辐射和风速，R2分别是0.75和0.43。 结论 涡度相关法在缙云山针阔叶混交林生态系统的监测过程中具有较好的适用性，且通量监测的数据来源可信，质量评价良好。研究期内，该生态系统处于碳汇过程，生长季的碳汇能力显著高于非生长季。光合有效辐射和风速是影响碳通量变化的主要环境因子。

Eddy Covariance Applicability and Carbon Flux Variation Characteristics of Coniferous and Broad-leaved Mixed Forests in Jinyun Mountain

Objective To provide helpful insights into forest management and sustainable forestry development, the applicability of eddy covariance method in the coniferous and broad-leaved mixed forest in Jinyun Mountain was explored and the carbon source or sink of the coniferous and broad-leaved mixed forest ecosystem was clarified. Method Used the eddy covariance observation method(EC) to obtain the carbon flux monitoring data of the coniferous and broad-leaved mixed forest in Jinyun Mountain from 2019.11 to 2020.10. Through turbulence data quality evaluation, energy closure and flux footprint analysis, the applicability of the eddy covariance to the underlying surface was verified. The changes of carbon flux in the ecosystem were analyzed, and the carbon source or sink in the study area were evaluated. Results During the study period, the turbulence data quality check of sensible heat flux(H), latent heat flux(LE) and carbon flux(Fc) was good, and the proportions of high-quality data were 77%, 61% and 62% respectively. During the growing season(April-October), the upper-layer energy closure rate was 0.82, and the lower-layer energy closure rate was 0.73. The direction of the high flux contribution area was consistent with the main wind direction (northeast)The. During the study period, the annual carbon sequestration of the ecosystem was 887.40 g·m−2. The monthly average daily changes and seasonal average daily changes were mostly bimodal, and the cumulative change of Fc was −826.2 g·m−2 in the growing season and −61.2 g·m−2 in the non-growing season. The main environmental factors affecting carbon flux were photosunthetically active radiation and wind speed, and R2 was 0.75 and 0.43, respectively. Conclusion The EC had good applicability in the monitoring process of the Jinyun Mountain coniferous and broad-leaved mixed forest ecosystem, and flux monitoring data are creadible, and flux quality check is evaluated well. During the study period, the ecosystem is in the process of carbon sink,and the carbon sink capacity in the growing season is significantly higher than that in the non-growing season. Photosynthetically active radiation and wind speed are the main environmental factors affecting carbon flux changes.