气候变化领域集成服务门户(CCPortal): Effect of Forest Canopy Structure on Wintertime Land Surface Albedo: Evaluating CLM5 Simulations With In-Situ Measurements

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DOI	10.1029/2020JD034118
	Effect of Forest Canopy Structure on Wintertime Land Surface Albedo: Evaluating CLM5 Simulations With In-Situ Measurements
	Malle J.; Rutter N.; Webster C.; Mazzotti G.; Wake L.; Jonas T.
发表日期	2021
ISSN	2169897X
卷号	126 期号:9
英文摘要	Land Surface Albedo (LSA) of forested environments continues to be a source of uncertainty in land surface modeling, especially across seasonally snow covered domains. Assessment and improvement of global scale model performance has been hampered by the contrasting spatial scales of model resolution and in-situ LSA measurements. In this study, point-scale simulations of the Community Land Model 5.0 (CLM5) were evaluated across a large range of forest structures and solar angles at two climatically different locations. LSA measurements, using an uncrewed aerial vehicle with up and down-looking shortwave radiation sensors, showed canopy structural shading of the snow surface exerted a primary control on LSA. Diurnal patterns of measured LSA revealed strong effects of both azimuth and zenith angles, neither of which were adequately represented in simulations. In sparse forest environments, LSA were overestimated by up to 66%. Further analysis revealed a lack of correlation between Plant Area Index (PAI), the primary canopy descriptor in CLM5, and measured LSA. Instead, measured LSA showed considerable correlation with the fraction of snow visible in the sensor's field of view, a correlation which increased further when only considering the sunlit fraction of visible snow. The use of effective PAI values as a simple first-order correction for the discrepancy between measured and simulated LSA in sparse forest environments substantially improved model results (64%–76% RMSE reduction). However, the large biases suggest the need for a more generic solution, for example, by introducing a canopy metric that represents canopy gap fraction rather than assuming a spatially homogeneous canopy. © 2021. The Authors.
英文关键词	Canopy shading; Land Surface Albedo; UAV measurements
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185253
作者单位	Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom; WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
推荐引用方式 GB/T 7714	Malle J.,Rutter N.,Webster C.,et al. Effect of Forest Canopy Structure on Wintertime Land Surface Albedo: Evaluating CLM5 Simulations With In-Situ Measurements[J],2021,126(9).
APA	Malle J.,Rutter N.,Webster C.,Mazzotti G.,Wake L.,&Jonas T..(2021).Effect of Forest Canopy Structure on Wintertime Land Surface Albedo: Evaluating CLM5 Simulations With In-Situ Measurements.Journal of Geophysical Research: Atmospheres,126(9).
MLA	Malle J.,et al."Effect of Forest Canopy Structure on Wintertime Land Surface Albedo: Evaluating CLM5 Simulations With In-Situ Measurements".Journal of Geophysical Research: Atmospheres 126.9(2021).