中文摘要：

以2010年6月～2011年5月三峡澎溪河回水区CO2与CH4通量监测数据为基础，参考澎溪河高阳平湖水域全年4次的24h昼夜连续跟踪观测结果，对每月各采样点的Et通量值进行估算。提出了水下地形划分法和环境因素控制法，将各采样点日通量数据外延至整个回水区水域，并估算了澎溪河回水区水域CO2与CH4年总通量值。研究期间，澎溪河回水区全年各采样点CO2通量均值为（3．05±0．46）mmol／（㎡·h）；CH4为（0．0501±0．0096）mmol／（㎡·h）。以水下地形法为基础，该水域全年CO2和CH4总通量分别为40060．5t和540．9t；以环境因素控制法为基础，全年CO2与CH4总通量分别为39073．0t和467．2t。以环境要素控制法为参考，该水域CO：全年平均释放强度为43．26mm01／（㎡·d），在全球水库数据序列中处于中等略偏高水平，CH4全年平均释放强度为1．42mmol／（㎡·d），在全球水库序列中处于中等水平。

英文摘要：

Estimation on annual greenhouse gas fluxes in reservoirs is crucial for the assessment of reservoir green- house gas effects. A la research was conducted in Pengxi River backwater area, Three Gorges Reservoir to estimate annual water-air CO2 and CH4 fluxes. Taken the 24h continuous monitoring data in Gaoyang Lake as reference, 2 methods, i.e. underwater topographical method and environmental controlling factor method, were carried out to esti- mate the annual fluxes based on monthly field data. The field sampling results showed that mean value of the CO2 flu- xes among the sampling spot was （3.05 ±0.46） mmol/（㎡·h） , while that of CH4 was （0. 050 1±0. 0096） mmol/ （ ㎡·h）. The annual estimation of CO2 and CH4 fluxes in the Pengxi River backwater area based on underwater topo- graphical method was 40 060.5 t and 540.9 t respectively. With the environmental controlling factor method, the an- nual estimation of CO2 and CH4 fluxes was 39 073.0 t and 467.2 t respectively. Taken the annual estimation result from environmental controlling factor method as reference, the weighted average CO2 fluxes during the study was 43.26 retool/（ ㎡·d） , while that of CH4 was 1.42 mmol/（ ㎡·d）. Generally, both of the CO2 and CH4 weight aver- age fluxes were shown to be in the mid-range in the global data sets, although that of CO2 was showed in slightly high- er bound.