Page 217 - 《高原气象》2022年第1期

1 期 杨 斌等：青藏高原东部拉萨河下游地区大气湍流交换特征研究 215

Study on the Characteristics of Atmospheric Turbulence Exchange

in the Lower Reaches of the Lhasa River in the
Eastern Qinghai-Xizang Plateau

YANG Bin ，YUAN Qi ，TAN Changhai ，ZHANG Gong ，ZHENG Ning ，GU Lianglei 4，5
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（1. Comprehensive Survey Command Center for Natural Resources，China Geological Survey，Beijing 100055，China；
2. Research Institute of Forestry，Chinese Academy of Forestry，Beijing 100091，China；
3. School of Atmospheric Sciences，SUN YAT-SEN University，Zhuhai 519082，Guangdong，China；
4. Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions，Northwest Institute of
Eco-Environment and Resources，Chinese Academy of Sciences，Lanzhou 730000，Gansu，China；
5. Nagqu Station of Plateau Climate and Environment，Northwest Institute of Eco-Environment and Resources，
Chinese Academy of Sciences，Lanzhou 730000，Gansu，China）

Abstract：Matter and energy between the land and atmosphere are transported with turbulent movement. Eddy
covariance technology is an important way to evaluate atmospheric resources. It plays an important role in turbu‐
lence characteristics and accurate flux observation research. In this study，we analyzed the characteristics and
similarity of turbulence spectra under different atmosphere conditions in the growing and non-growing seasons
using closed-path eddy covariance system of Caigongtang flux station for the underlying surface of the typical
grassland in the lower reaches of the Lhasa River in the eastern Qinghai-Xizang Plateau from August to Novem‐
ber，2020. The results showed：（1）During the growing season from August to September，the average daily net
ecosystem CO exchange（NEE）was -2. 3 gC·m ·d ，and the average daily ET was 1. 8 mm·day ，During the
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non-growing season from October to November，the average daily NEE was 1. 1 gC·m ·d ，and the average
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daily ET was 0. 3 mm·day ；（2）The normalized spectra of three-dimensional（u，v and w）direction of turbu‐
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lent wind speed and temperature had obvious sub-regions of inertia，the slope of the spectra density curve con‐
formed to the -2/3 law，and the normalized co-spectra of the vertical direction（w）turbulent wind speed and tem‐
perature，CO and H O gas concentrations is higher than -4/3 law；（3）The daily variation of atmosphere stabili‐
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ty during the growing and non-growing seasons was similar，mainly decreasing with the increase of momentum
flux，but the normalized standard deviation（σ/u * ）fitting results of wind speed in each direction were different.
During the growing season，σ u /u * ，σ v /u * ，and σ w /u * were 2. 84，2. 73，and 1. 07，respectively. During the non-
growing season，the three increased to 3. 23，3. 19，and 1. 22，respectively. The increase in normalized standard
deviation of horizontal wind speed was obvious during the non-growing season，so the parameterization scheme
of the similarity law of turbulent wind speed during the growing and non-growing seasons should be considered
separately. The closed-path eddy covariance system can better realize the flux observation in this study area，and
this conclusion can provide the basis for the land surface parameterization scheme that considers the similarity of
the turbulent wind speed during the growing and non-growing seasons，which helps to observe the atmospheric
resources more accurately.
Key words：Qinghai-Xizang Plateau；carbon and water flux；turbulence spectra；normalized standard deviation
similarity law；atmosphere stability