| Turbulent Variance Characteristics of Temperature and Humidity over a Non-uniform Land Surface for an Agricultural Ecosystem in China |
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| 作者姓名： | 高志球 卞林根 谌志刚 张佳华 |
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| 作者单位： | [1]Chinese Academy of Meteorological Sciences, Beijing 100081 [2]State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry （ LAPC~, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 [3]Guangzhou Central Meteorological Observatory, Guangzhou 510080 [4]International CLIVAR Project Office, Southampton Oceanography Centre, Southampton, U.K. |
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| 基金项目： | Chinese Academy of Science through the Hundred Talents，Ministry of Science and Technology of China through the National Key Basic Research and Development Project of China，国家自然科学基金，Jiangsu Key Laboratory of Meteorological Disaster (Nanjing University of Information Science and Technology) |
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| 摘 要： | This paper describes the application of the variance method for flux estimation over a mixed agricultural region in China. Eddy covariance and flux variance measurements were conducted in a near-surface layer over a non-uniform land surface in the central plain of China from 7 June to 20 July 2002. During this period, the mean canopy height was about 0.50 m. The study site consisted of grass (10% of area), beans (15%), corn (15%) and rice (60%). Under unstable conditions, the standard deviations of temperature and water vapor density (normalized by appropriate scaling parameters), observed by a single instrument, followed the Monin-Obukhov similarity theory. The similarity constants for heat (CT ) and water vapor (Cq) were 1.09 and 1.49, respectively. In comparison with direct measurements using eddy covariance techniques, the flux variance method, on average, underestimated sensible heat flux by 21% and latent heat flux by 24%, which may be attributed to the fact that the observed slight deviations (20% or 30% at most) of the similarity “constants” may be within the expected range of variation of a single instrument from the generally-valid relations.
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| 关 键 词： | 旋水 协方差 通量方差 土地覆盖率 农业生态系统 |
| 收稿时间： | 2005-07-20 |
| 修稿时间： | 2005-10-14 |
Turbulent variance characteristics of temperature and humidity over a non-uniform land surface for an agricultural ecosystem in China |
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| Zhiqiu Gao,Lingen Bian,Zhigang Chen,Michael Sparrow,Jiahua Zhang.Turbulent Variance Characteristics of Temperature and Humidity over a Non-uniform Land Surface for an Agricultural Ecosystem in China[J].Advances in Atmospheric Sciences,2006,23(3):365-374. |
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| Authors: | Zhiqiu Gao Lingen Bian Zhigang Chen Michael Sparrow Jiahua Zhang |
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| Institution: | Chinese Academy of Meteorological Sciences, Beijing 100081, State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029,Chinese Academy of Meteorological Sciences, Beijing 100081,Guangzhou Central Meteorological Observatory, Guangzhou 510080,International CLIVAR Project Office, Southampton Oceanography Centre, Southampton, U.K.,Chinese Academy of Meteorological Sciences, Beijing 100081 |
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| Abstract: | This paper describes the application of the variance method for flux estimation over a mixed agricultural region in China. Eddy covariance and flux variance measurements were conducted in a near-surface layer over a non-uniform land surface in the central plain of China from 7 June to 20 July 2002. During this period, the mean canopy height was about 0.50 m. The study site consisted of grass (10% of area), beans (15%), corn (15%) and rice (60%). Under unstable conditions, the standard deviations of temperature and water vapor density (normalized by appropriate scaling parameters), observed by a single instrument,followed the Monin-Obukhov similarity theory. The similarity constants for heat (CT) and water vapor (Cq) were 1.09 and 1.49, respectively. In comparison with direct measurements using eddy covariance techniques, the flux variance method, on average, underestimated sensible heat flux by 21% and latent heat flux by 24%, which may be attributed to the fact that the observed slight deviations (20% or 30% at most) of the similarity "constants" may be within the expected range of variation of a single instrument from the generally-valid relations. |
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| Keywords: | turbulent fluxes eddy covariance flux variance non-uniform land surface |
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