荒漠河岸胡杨林生态系统能量分配及蒸散发

生态输水工程使得黑河下游地区荒漠河岸林的面积得到了恢复，为进一步巩固生态恢复的成果，非常有必要深入研究胡杨林生态系统的水热交换过程及其对环境因子和人类活动的响应机理。基于涡度相关技术，对2013-2016年荒漠河岸胡杨林生态系统的水热交换过程进行了研究，得出的主要结论如下：（1）生长季生态系统的能量消耗以潜热通量为主，波文比为0.21；非生长季则以感热通量为主，波文比为3.61；春季和秋季的灌水过程，使得胡杨生长前期和后期的潜热通量值较高，直接影响着胡杨林生态系统的能量分配。（2）灌水的时间改变了潜热通量和蒸散发的季节变化过程，而灌水的量决定着春季和秋季潜热通量和蒸散量的年际差异。（3）2014-2016年，生态系统的年蒸散量和生长季蒸散量平均分别为1092 mm和932 mm。荒漠河岸胡杨林生态系统的蒸散量主要受系统水分状况（灌水量）及植物生长状况的影响。

Energy partitioning and evapotranspiration of Populus euphratica forests in desert riparian area

The area of desert riparian Populus euphratica forest has been restored since the implementation of the ecological water transfer project in Heihe River in 2001. To support the current efforts in conservation, more knowledge is needed on energy and water exchange and its response to biophysical factors and human activities. Based on the eddy covariance technique, the processes and mechanisms of energy and water exchange were studied over the Populus euphratica forest ecosystem from 2013-2016. Results were showed as follows: (1) In the growing season, the energy consumption was dominated by latent heat flux, the value of bowen ratio was 0.21; while the energy consumption was dominated by sensible heat flux in non-growing season, the value of bowen ratio was 3.61. Irrigation events in spring and autumn made the value of latent heat flux in the early and late growth of Populus euphratica higher, which directly affected the energy partitioning. (2) The patterns of seasonal variation in evapotranspiration and latent heat flux were changed by the time of irrigation. In addition, the annual variability of evapotranspiration and latent heat flux in spring and autumn were controlled by the amount of irrigation. (3) The cumulative evapotranspiration for an entire year and growing season were estimated as 1092 mm and 932 mm, respectively. The evapotranspiration in the growing season was controlled by the system water status (irrigation events) and plant phenology.