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	Simulation of crop growth and energy and carbon dioxide fluxes at different time steps from hourly to daily
	Wang J.; Yu Q.; Wang J.
	2007
关键词	photosynthesis transpiration stomatal conductance CO2 flux evapotranspiration coupled model diurnal variation winter wheat model partial canopy cover latent-heat flux parameterization scheme amazonian deforestation tropical deforestation stomatal conductance photosynthesis model leaf photosynthesis field verification surface processes
英文摘要	Understanding the exchange processes of energy and carbon dioxide (CO2) in the soil-vegetation -atmosphere system is important for assessing the role of the terrestrial ecosystem in the global water and carbon cycle and in climate change. We present a soil- vegetation -atmosphere integrated model (ChinaAgrosys) for simulating energy, water and CO, fluxes, crop growth and development, with ample supply of nutrients and in the absence of pests, diseases and weed damage. Furthermore, we test the hypotheses of whether there is any significant difference between simulations over different time steps. CO2, 41 water and heat fluxes were estimated by the improving parameterization method of the coupled photosynthesis- stomatal conductance -transpiration model. Soil water evaporation and plant transpiration were calculated using a multilayer water and heat-transfer model. Field experiments were conducted in the Yucheng Integrated Agricultural Experimental Station on the North China Plain. Daily weather and crop growth variables were observed during 1998-2001, and hourly weather variables and water and heat fluxes were measured using the eddy covariance method during 2002-2003. The results showed that the model could effectively simulate diurnal and seasonal changes of net radiation, sensible and latent heat flux, soil heat flux and CO2 fluxes. The processes of evapotranspiration, soil temperature and leaf area index agree well with the measured values. Midday depression of canopy photosynthesis could be simulated by assessing the diurnal change in canopy water potential. Moreover, the comparisons of simulated daily evapotranspiration and net ecosystem exchange (NEE) under different time steps indicated that time steps used by a model affect the simulated results. There is no significant difference between simulated evapotranspiration using the model under different time steps. However, simulated NEE produces large differences in the response to different time steps. Therefore, the accurate calculation of average absorbed photosynthetic active radiation is important for the scaling of the model from hourly steps to daily steps in simulating energy and CO, flux exchanges between winter wheat and the atmosphere. Copyright (C) 2007 John Wiley & Sons, Ltd.
出处	Hydrological Processes
卷	21
期	18
页	2474-2492
收录类别	SCI
语种	英语
ISSN号	0885-6087
内容类型	SCI/SSCI论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/22939]
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	Wang J.,Yu Q.,Wang J.. Simulation of crop growth and energy and carbon dioxide fluxes at different time steps from hourly to daily. 2007.

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