中文摘要：

利用涡度相关技术对三江平原典型沼泽湿地蒸散量及其影响因子进行研究，结果表明沼泽湿地蒸散量时间变化特征明显。日出后蒸散量逐渐增加，12：００～13：00（北京时间）达到最大值，6～10月各月平均值分别为285．5、257．4、243．0、167．１和65．9W·m^-2，各月总蒸散量分别为120．9、101．6、93．1、59．3和25．9mm。与同期降雨量相比，6～9月沼泽湿地水量发生亏缺，亏缺量分别为72．7、3．2、58．8和44．4mm。沼泽湿地蒸散量受环境因子影响强烈。蒸散量与净辐射呈显著线性正相关。蒸散量也随饱和水汽压差的增加而增加，但植物发育成熟后，当饱和水汽压差大于某一阈值（11hPa）时，饱和水汽压差的增加反而抑制了水分蒸散。另外，白天风速增加在一定程度上能够促进水分蒸散。

英文摘要：

Evapotranspiration and its influential factors were studied by eddy covariance technique over mire in the San- jiang Plain in 2004. The results show that temporal variation of evapotranspiration is very clear. The evapotransplration gradually increased after the sunrise and reached the maximum at noon from June to October, which were 285. 5, 257. 4, 243.0, 167. 1, and 65.9 W ·m^-2 , respectively. The total evapotranspiration of every month from June to October were 120. 9, 101.6, 93.1, 59.3, and 25.9 mm, respectively. Compared with the corresponding precipitation, the deficits of water for mire ecosystem occurred from June to September, which were about 72. 7, 3.2, 58. 8, and 44. 4 mm, respectively. The results also suggest that evapotranspiration is significantly influenced by environmental factors. Evapotranspiration in the daytime, for example, is strongly linearly dependent on net radiation and increased with the increasing vapour pressure deficit. Howcvcr, after mirc plant matured, thc evapotranspiration was depressed by the increasing vapour pressure deficit when it surpassed certain value （11 hPa）. In addition, wind speed could promote the evapotranspiratlon at some degree in the daytime.