神农架大九湖泥炭湿地CH4通量特征及其影响因子
Characteristics of Methane Flux and Their Effect Factors on Dajiuhu Peatland of Shennongjia

开展大九湖湿地生态系统CH4通量研究，对深入了解碳循环机制、科学经营以及准确评估湿地生态系统碳收支等方面具有重要意义.以湖北省神农架林区大九湖亚高山泥炭湿地为研究区域，采用涡度相关法对CH4通量进行原位连续观测，分析了泥炭湿地CH4通量变化特征及其影响因素.结果表明，大九湖泥炭湿地在2015年8月至2016年5月期间表现为CH4的源，日通量均值为15.57nmol·m-2·s-1.CH4通量具有“夜间极大值”(2∶00或22∶00)和“三峰模式”(6∶00、12∶00和22∶00)两种昼夜变化规律；CH4通量具有明显季节变化规律，8月释放最多(36.46nmol·m-2·s-1)，3月释放最少(3.92nmol·m-2·s-1).相关性分析表明，大九湖泥炭湿地CH4通量受空气温度(Ta)、土壤温度(Ts)、土壤含水量(SWC)和摩擦风速(U*)的共同影响；不同时间尺度上， 各影响因子与CH4通量的相关性有所差异.曲线拟合得出，CH4通量与Ta和Ts呈指数增长趋势，与SWC呈二次曲线关系.
It is significant to do research on methane flux in Dajiuhu, to understand mechanism of the carbon cycle better, to manage it more scientifically and to assess the carbon balance in wetland ecosystem accurately. By using eddy covariance technique, methane fluxes of Dajiuhu subalpine peatland in Shennongjia Forestry Administrative District of Hubei Province, Central China were observed from August 2015 to May 2016, and temporal variation of methane emission and related affecting factors were investigated. The results show that the peatland ecosystem was methane sources, with the daily average release rate being 15.57 nmol·m-2·s-1. During the sampling period, the mean diurnal variations showed a maximum value at night (2∶00 or 22∶00) and a threepeak pattern all day (6∶00, 12∶00 and 22∶00). The monthly average emission rate of CH4 decreased rapidly from August(36.46 nmol·m-2·s-1), and its valley in March(3.92 nmol·m-2·s-1), then increasing gradually from April. The correlation analysis indicates that CH4 flux was mainly dominated by air temperature (Ta), soil temperature (Ts), soil water content (SWC) and friction velocity (U*). And their relevance varied with different time scales. The curve fitting shows that CH4 flux was an exponential correlated with Ta and Ts, and had a good conic relationship with SWC