Modeling winter wheat phenology and carbon dioxide fluxes at the ecosystem scale based on digital photography and eddy covariance data
Zhang L.; Zhang L.
2013
关键词Digital camera Greenness index Phenological date Gross primary production Winter wheat gross primary production north china plain deciduous broadleaf forest leaf-area index growing-season use efficiency vegetation phenology spatial variability repeat photography temporal variation
英文摘要Recent studies have shown that the greenness index derived from digital camera imagery has high spatial and temporal resolution. These findings indicate that it can not only provide a reasonable characterization of canopy seasonal variation but also make it possible to optimize ecological models. To examine this possibility, we evaluated the application of digital camera imagery for monitoring winter wheat phenology and modeling gross primary production (GPP). By combining the data for the green cover fraction and for GPP, we first compared 2 different indices (the ratio greenness index (green-to-red ratio, G/R) and the relative greenness index (green to sum value, G%)) extracted from digital images obtained repeatedly over time and confirmed that G/R was best suited for tracking canopy status. Second, the key phenological stages were estimated using a time series of G/R values. The mean difference between the observed phenological dates and the dates determined from field data was 33 days in 2011 and 4 days in 2012, suggesting that digital camera imagery can provide high-quality ground phenological data. Furthermore, we attempted to use the data (greenness index and meteorological data in 2011) to optimize a light use efficiency CLUE) model and to use the optimal parameters to simulate the daily GPP in 2012. A high correlation (R-2 = 0.90) was found between the values of LUE-based GPP and eddy covariance (EC) tower-based GPP, showing that the greenness index and meteorological data can be used to predict the daily GPP. This finding provides a new method for interpolating GPP data and an approach to the estimation of the temporal and spatial distributions of photosynthetic productivity. In this study, we expanded the potential use of the greenness index derived from digital camera imagery by combining it with the LUE model in an analysis of well-managed cropland. The successful application of digital camera imagery will improve our knowledge of ecosystem processes at the temporal and spatial levels. (C) 2013 Elsevier B.V. All rights reserved.
出处Ecological Informatics
18
69-78
收录类别SCI
语种英语
ISSN号1574-9541
内容类型SCI/SSCI论文
源URL[http://ir.igsnrr.ac.cn/handle/311030/29995]  
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
Zhang L.,Zhang L.. Modeling winter wheat phenology and carbon dioxide fluxes at the ecosystem scale based on digital photography and eddy covariance data. 2013.
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