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| DOI： |
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| Analyzing Flux Footprint of Agro-ecosystem Measured by the Eddy Covariance System |
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FENG Junting, HU Zhenhua, ZHANG Baozhong, ZHOU Qingyun, PENG Zhigong
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Forestry College，Shanxi Agriculture University, Taigu 030801, China; State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China;National Center of Efficient Irrigation Engineering and Technology Research-Beijing， Beijing 100048，China
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| Abstract: |
| Using FSAM and KL models and flux data measured during the growing stage of winter wheat from the eddy covariance system in Beijing, we analyzed the flux footprints under different atmospheric conditions and growing stages. The results are summarized as follows. ①The prevailing wind direction was in 270o~360o and the wind frequency under stable and unstable atmospheric conditions was 42% and 37% respectively in the same direction. ②The flux footprint under prevailing wind direction varied at different growing stages and atmospheric conditions; when the atmospheric condition was stable, the upwind range of the flux footprint was 16.07~167.05 m, while when the atmospheric condition was unstable, the upwind range of flux footprint was 13.73~153.66 m. The flux footprint under stable atmospheric condition was higher than that under unstable atmospheric condition, and the upwind footprint increased first then decreased within the growing stages. ③Comparative analysis of the FSAM and KL models showed that the longest distances from the observation point estimate by the FSAM model and KL model were 215.8 m and 291.8 m respectively. The results estimated by the two models at different growing stages differed. |
| Key words: eddy covariance system; flux footprint; FSAM model; KL model; winter wheat |
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