气候变化领域集成服务门户(CCPortal): In-situ spectroscopy and shortwave radiometry reveals spatial and temporal variation in the crown-level radiative performance of urban trees

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DOI	10.1016/j.rse.2020.112231
	In-situ spectroscopy and shortwave radiometry reveals spatial and temporal variation in the crown-level radiative performance of urban trees
	Deng J.; Pickles B.J.; Shao L.
发表日期	2021
ISSN	00344257
卷号	253
英文摘要	In conventional microclimate environment modelling, and the development of tree planning strategies for urban heat mitigation, tree crown surface albedo for any given species is assumed to be a constant. However, our recent research into urban tree radiative performance at the crown level implied that tree crown surface albedo changes over time. Based on the in-situ spectroscopy protocols established previously to measure tree crown transflectance, variation in the characteristics of tree crown surface albedo was explored combining spectroscopy and solar shortwave radiometry. Three commonly planted native UK tree species, Carpinus betulus, Acer campestre, and Taxus baccata, were sampled. Spatial distribution profiles of tree crown transflectance measured at fixed solar altitudes were normalised by in-situ spectroradiometry. Tree crown transflectance in the near infrared (NIR) region was found to be proportionally linked to tree crown surface albedo. Within each species, mean tree crown transflectance in the NIR region of 800–900 nm was approximately 2.5 times tree crown surface albedo. It was further found that infrared radiation (700–2500 nm) accounted for more than 90% of the total transflected shortwave radiation from tree crowns. The results demonstrate that tree crown surface albedo linearly increases with momentary solar altitude and the maximum tree crown surface albedo corresponds to maximum solar altitude at solar noon on sunny days in summer. Tree crown surface albedo across species tends to be strongly dependent on leaf size if considering visibly dense crown foliage. Our findings provide important insights into tree radiative shading effects resulting from temporal variation in tree crown surface albedo, with consequences for urban microclimate modelling and the development of urban heat mitigation strategies. © 2020 Elsevier Inc.
英文关键词	In-situ spectroscopy; Infrared radiation; Radiative performance; Shortwave radiometry; Transflectance; Tree crown surface albedo; Urban microclimate; Urban trees
语种	英语
scopus关键词	Infrared devices; Infrared radiation; Planning; Radiometry; Solar radiation; Uranium metallography; Distribution profiles; Environment modelling; In-situ spectroscopy; Near infrared region; Planning strategies; Short-wave radiation; Spatial and temporal variation; Surface albedo change; Forestry; altitude; canopy architecture; infrared radiation; microclimate; shading; shortwave radiation; spatial variation; temporal variation; urban ecosystem; United Kingdom; Acer campestre; Carpinus betulus; Taxus baccata
来源期刊	Remote Sensing of Environment
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/179016
作者单位	School of The Built Environment, University of Reading, Whiteknights, Reading, Berkshire, RG6 6DF, United Kingdom; School of Biological Sciences, University of Reading, Harborne Building, Whiteknights, Reading, RG6 6AS, United Kingdom
推荐引用方式 GB/T 7714	Deng J.,Pickles B.J.,Shao L.. In-situ spectroscopy and shortwave radiometry reveals spatial and temporal variation in the crown-level radiative performance of urban trees[J],2021,253.
APA	Deng J.,Pickles B.J.,&Shao L..(2021).In-situ spectroscopy and shortwave radiometry reveals spatial and temporal variation in the crown-level radiative performance of urban trees.Remote Sensing of Environment,253.
MLA	Deng J.,et al."In-situ spectroscopy and shortwave radiometry reveals spatial and temporal variation in the crown-level radiative performance of urban trees".Remote Sensing of Environment 253(2021).