Analysis of the relationship of ecosystem evapotranspiration and methane emission over the lowland evergreen forest under the tropical monsoon climate

在热带季风气候条件下，利用涡旋协方差方法测量了东南亚低地常绿森林上空甲烷和水汽的通量。在雨季，甲烷通量的日变化不明显，但日平均值表明森林生态系统有少量的甲烷排放。在旱季，从白天计算的甲烷通量可以看出，生态系统对甲烷有明显的吸收。在这两个季节，甲烷通量的日变化趋势与水汽通量的日变化趋势并不一致：这表明树木的蒸腾作用不是甲烷排放的动力，至少在低地常绿森林中是这样。

Fluxes of methane and water vapor were measured applying eddy covariance method over a lowland evergreen forest in the southeastern Asia under the tropical monsoon climate. In the rainy season, the diurnal variation of methane flux was not clearly observed, but the daily mean indicated the slight emission of methane from the forest ecosystem. In the dry season, the distinct methane absorption into the ecosystem was shown from the calculated flux in the daytime. For both seasons, the diurnal trends of methane flux were not corresponding to those of water vapor flux: The result suggested that the transpiration from the trees was not a motive force of methane emission, at least at the lowland evergreen forest.