Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests

Show simple item record 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. Mõttus, Matti Nemani, Ramakrishna R. Piao, Shilong Poulter, Benjamin Saleska, Scott R. Saatchi, Sassan S. Xu, Liang Zhou, Liming Myneni, Ranga B. 2016-05-13T07:49:01Z 2016-05-13T07:49:01Z 2015-06
dc.identifier.citation Bi , J , Knyazikhin , Y , Choi , S , Park , T , Barichivich , J , Ciais , P , Fu , R , Ganguly , S , Hall , F , Hilker , T , Huete , A , Jones , M , Kimball , J , Lyapustin , A I , Mõttus , M , Nemani , R R , Piao , S , Poulter , B , Saleska , S R , Saatchi , S S , Xu , L , Zhou , L & Myneni , R B 2015 , ' Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests ' , Environmental Research Letters , vol. 10 , no. 6 , 064014 .
dc.identifier.other PURE: 52742345
dc.identifier.other PURE UUID: 0acc5547-21a8-4c95-97da-e42980fcb24f
dc.identifier.other WOS: 000356835600016
dc.identifier.other Scopus: 84937509345
dc.description.abstract 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. en
dc.format.extent 6
dc.language.iso eng
dc.relation.ispartof Environmental Research Letters
dc.rights cc_by
dc.rights.uri info:eu-repo/semantics/openAccess
dc.subject Amazonian rainforests
dc.subject seasonality
dc.subject remote sensing
dc.subject MISR
dc.subject MODIS
dc.subject LEAF-AREA INDEX
dc.subject DRY SEASON
dc.subject CARBON
dc.subject VARIABILITY
dc.subject SENSITIVITY
dc.subject ALGORITHM
dc.subject PHENOLOGY
dc.subject 1172 Environmental sciences
dc.title Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests en
dc.type Article
dc.contributor.organization Department of Geosciences and Geography
dc.description.reviewstatus Peer reviewed
dc.relation.issn 1748-9326
dc.rights.accesslevel openAccess
dc.type.version publishedVersion

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