长白山阔叶红松林林冠大气界面湍流主导时间尺度特征

使用多尺度分析方法分析了长白山阔叶红松林林冠大气界面湍流交换的主导时间尺度特征及相应的作用系数特征及大气层结和林冠结构的影响。发现:水平风速的DTS大于垂直风速的相应值,垂直风速的DCR大于水平风速的DCR。大气层结影响是非线性的。不稳定层结条件下的DTS和DCR大于稳定层结下。在强稳定层结和强不稳定层结条件下,DTS和DCR主要取决于来流特征。生长季节各高度DTS的变化规律较为复杂且不一致,非生长季节各高度具有一致的变化。不稳定层结条件下的生长季节水平风速DTS大于非生长季节;林冠结构可以显著影响主导时间尺度和主导过程贡献率。图2表1参15。

Dominate time scale characteristics of the turbulence across canopy-atmosphere interface of a mixed broadleaved-Korean pine forest in Changbai Mountains

The measurement and observation for this study were carried out at Forest Ecosystem Opened Research Station of Changbai Mountains (128°28′E and 42°24′ N, Jilin Province, P. R. China). Characteristics of Dominant time scales (DTSes) and dominant time scales contribution ratios (DCRs) across canopy-atmosphere interface and controlling factors were analyzed with multi-scale method. DTS of stream wise and lateral velocity components were larger than that of vertical velocity component. While DCR of vertical velocity component was larger than that of the stream wise and lateral velocity components. Effect of atmospheric stability on DCR and DTS was nonlinear. DTS under unstable conditions was larger than that under stable conditions; DTS and DCR were determined upon the original scales characteristics of upwind flow under strong stability. Canopy structure would influence DTS and DCR across canopy-atmosphere interface remarkably. Foundation Item: This study was supported by the grand of the knowledge Innovation Program of the Chinese Academy of Sciences (KZCX1-SW-01) and National Natural Science Foundation (30070158). Biography: ZHANG Jun-hui (1973-), male, Ph. Doctor, assistant research fellow, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Chai Ruihai