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DOI	10.1088/1748-9326/10/6/064014
	Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests
	Bi, Jian; Knyazikhin, Yuri; Choi, Sungho; Park, Taejin; Barichivich, Jonathan; Ciais, Philippe; Fu, Rong; Ganguly, Sangram; Hall, Forrest; Hilker, Thomas; Huete, Alfredo; Jones, Matthew; Kimball, John; Lyapustin, Alexei I.; Mottus, Matti; Nemani, Ramakrishna R.; Piao, Shilong; Poulter, Benjamin; Saleska, Scott R.; Saatchi, Sassan S.; Xu, Liang; Zhou, Liming; Myneni, Ranga B.
通讯作者	Bi, J (通讯作者)
发表日期	2015
ISSN	1748-9326
卷号	10 期号:6
英文摘要	Resolving the debate surrounding the nature and controls of seasonal variation in the structure and metabolism of Amazonian rainforests is critical to understanding their response to climate change. In situ studies have observed higher photosynthetic and evapotranspiration rates, increased litterfall and leaf flushing during the Sunlight-rich dry season. Satellite data also indicated higher greenness level, a proven surrogate of photosynthetic carbon fixation, and leaf area during the dry season relative to the wet season. Some recent reports suggest that rainforests display no seasonal variations and the previous results were satellite measurement artefacts. Therefore, here we re-examine several years of data from three sensors on two satellites under a range of sun positions and satellite measurement geometries and document robust evidence for a seasonal cycle in structure and greenness of wet equatorial Amazonian rainforests. This seasonal cycle is concordant with independent observations of solar radiation. Weattribute alternative conclusions to an incomplete study of the seasonal cycle, i. e. the dry season only, and to prognostications based on a biased radiative transfer model. Consequently, evidence of dry season greening in geometry corrected satellite data was ignored and the absence of evidence for seasonal variation in lidar data due to noisy and saturated signals was misinterpreted as evidence of the absence of changes during the dry season. Our results, grounded in the physics of radiative transfer, buttress previous reports of dry season increases in leaf flushing, litterfall, photosynthesis and evapotranspiration in well-hydrated Amazonian rainforests.
关键词	LEAF-AREA INDEX TROPICAL FOREST MODIS PATTERNS CARBON VARIABILITY SENSITIVITY ALGORITHM PHENOLOGY FLUXES
英文关键词	Amazonian rainforests; seasonality; remote sensing; MISR; MODIS
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS类目	Environmental Sciences ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000356835600016
来源期刊	ENVIRONMENTAL RESEARCH LETTERS
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258620
推荐引用方式 GB/T 7714	Bi, Jian,Knyazikhin, Yuri,Choi, Sungho,et al. Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests[J]. 中国科学院青藏高原研究所,2015,10(6).
APA	Bi, Jian.,Knyazikhin, Yuri.,Choi, Sungho.,Park, Taejin.,Barichivich, Jonathan.,...&Myneni, Ranga B..(2015).Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests.ENVIRONMENTAL RESEARCH LETTERS,10(6).
MLA	Bi, Jian,et al."Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests".ENVIRONMENTAL RESEARCH LETTERS 10.6(2015).