Turbulence flux measurement above the overstory of a subtropical Pinus plantation over the hilly region in southeastern China
文献类型：SCI/SSCI论文
| 作者 | Wen X. F. ; Yu G. R. ; Sun X. M. ; Liu Y. F. |
| 发表日期 | 2005 |
| 关键词 | eddy covariance power spectra cospectra Monin-Obukhov similarity energy balance closure nocturnal turbulence flux carbon-dioxide exchange long-term eddy covariance tall vegetation water-vapor forest energy aircraft terrain balance |
| 英文摘要 | Continuous turbulence flux measurement using the eddy covariance (EC) technique was made from January 1 to December 31 in 2003 at two and three canopy heights of a subtropical Pinus plantation on the red earth hilly region in southeastern China. To be able to make sure that the measured turbulence flux will equal the net ecosystem/atmosphere exchange, the quality of the data has to be assessed. Three criteria were investigated here, including the power spectra and cospectra analyses, flux variance similarity (integral turbulence test) and energy balance closure. The spectral analyses suggested that above-canopy power spectral slopes for all velocity components and scalars such as CO2, H2O and air temperature followed the expected -2/3 power law in the inertial subrange, and their cospectral slopes were close to -4/3 power law in the inertial subrange. The important contribution of large-scale motions to energy and mass transfer above the canopy at higher measurement level was also confirmed by the spectral analyses. The eddy covariance systems have the ability to resolve fluctuations associated with small-scale eddies and did not induce an obvious underestimation of the measured turbulence flux. The Monin-Obukhov similarity functions for the normalized standard deviation of vertical wind speed and air temperature were well-defined functions of atmospheric stability at two heights above the forest canopy, which indicated that turbulence flux measurements made at two heights were within the surface layer. Nocturnal flux underestimation and departures of this normalized standard deviation of vertical wind speed similarity function from that expected from Monin-Obukhov theory were a function of friction velocity. Thus, an optimal criterion of friction velocity was determined to be greater than 0.2-0.3 m s(-1) for nocturnal fluxes so that the eddy covariance flux measurement was under high turbulent mixing conditions. Energy balance closure reached about 72%-81% at the studied site, which was comparable to the 10%-30% of energy imbalance reported in the literature. However, the energy balance closure could be only used as a useful reference criterion. |
| 出处 | Science in China Series D-Earth Sciences |
| 卷 | 48 |
| 页 | 63-73 |
| 收录类别 | SCI |
| 语种 | 英语 |
| ISSN号 | 1006-9313 |
| 源URL | [http://ir.igsnrr.ac.cn/handle/311030/22805]  |
| 专题 | 地理科学与资源研究所_历年回溯文献 |
| 推荐引用方式 GB/T 7714 | Wen X. F.,Yu G. R.,Sun X. M.,et al. Turbulence flux measurement above the overstory of a subtropical Pinus plantation over the hilly region in southeastern China. 2005. |
入库方式： OAI收割
来源：地理科学与资源研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。