寒温带森林沼泽湿地近地表CH4浓度变化特征研究

甲烷(CH4)是重要的增温气体,在气候变化敏感的寒温带森林地区,土壤CH4排放量的估算和排放机制存在很大的不确定性。本文以研究寒温带森林沼泽湿地CH4浓度变化特征为主要目的进行研究。采用LGR快速甲烷分析仪(FMA)定位连续测定大兴安岭天然林沼泽湿地近地表CH4浓度及其水汽浓度,分析了森林沼泽湿地CH4浓度的变化特征及其与水汽浓度的关系。结果表明:测定期内,寒温带森林沼泽湿地近地表CH4浓度日变化规律呈现明显的单峰日变化特征,日峰值出现时间12∶00左右;CH4浓度月变化规律呈现先减少后增大再下降的趋势。水汽浓度日变化规律呈双峰的变化特征,峰值呈现时间段分别为6∶00-12∶00之间、16∶00-19∶00之间。水汽浓度的月变化规律,呈现先增大后减少的趋势。沼泽湿地CH4浓度随着大气的水汽浓度升高而降低,呈现负相关关系,相关关系为:y=-0.00001x+2.0258(R^2=0.7257,P<0.05)。

Change Characteristics of Near-surface CH4 Concentration in Cold Temperate Forest Marsh Wetland

Methane(CH4)is a kind of important warming gas.In cold temperate forest areas which are sensitive to climate change,there are great uncertainties in the estimation and emission mechanism of soil CH4 emissions.In this paper,a rapid methane analyzer(FMA)based on LGR was used to continuously determine the near-surface CH4 concentration and water vapor concentration in forest marsh wetlands,and the change characteristics of CH4 concentration and its relationship with water vapor concentration in forest marsh wetlands were analyzed.The results showed that during the measurement period,the diurnal variation of near-surface CH4 concentration in cold temperate forest marsh wetland appeared obvious characteristics of single peak diurnal variation,with he daily peak occurring around 12∶00.The monthly change of CH4 concentration showed a trend of decreasing first,then increasing and decreasing again.The diurnal variation of water vapor concentration was characterized by a double-peak variation,with the two peaks appearing at the period of 6∶00-12∶00 and 16∶00-19∶00,respectively.The monthly variation of water vapor concentration showed a trend of increasing first and then decreasing.The CH4 concentration in marsh wetland decreased with the increase of atmospheric vapor concentration,which showed a negative correlation,the correlation was y=-0.00001x+2.0258(R 2=0.7257,P<0.05).