Turbulence Statistics within and above a Pine Forest
| Autor: | Li-Chung Huang, 黃立中 |
|---|---|
| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 This study investigates the canopy turbulence structure. Three-dimensional velocities and temperature were measured within and just above a pine forest. Vertical profiles of horizontal velocity, sensible heat flux, momentum stress, standard deviation, skewness coefficient, kurtosis coefficient and correlation coefficient are calculated for different thermal stabilitity conditions. In this study, the thermal stability is depends on the local heat flux profile instead of the thermal stability coefficient, usually used in the surface layer. Furthermore, this study analyzes the structure of canopy turbulence by quadrant analysis, ramps analysis, autocorrelation, crosscorrelation, and shannon entropy. The purpose of this study is to understand the structure of the canopy turbulence under different thermal stabilities, and aims at a parameterization framework of turbulent statistics for implementation in the Lagrangian stochastics models. The most important results include: 1) the turbulence characteristics of longitudinal velocity for the upper canopy and the lower canopy are different; 2) Gaussian entropy deficit is more efficient in identifying the Gaussian turbulence than the higher-order statistics; 3) thermal stability did not play an important role in lower-order velocities statistics but influence obviously on the statistics of the higher-order velocities and all temperature; 4) the eddy size is increased with decreasing the heat flux. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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