DOI: 10.1002/2017JD026581
论文题名: Improving representation of canopy temperatures for modeling subcanopy incoming longwave radiation to the snow surface
作者: Webster C. ; Rutter N. ; Jonas T.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2017
语种: 英语
英文关键词: Canopy radiation transfer
; Canopy temperatures
; Forest canopy structure
; Longwave radiation
; Thermal infrared imagery
英文摘要: A comprehensive analysis of canopy surface temperatures was conducted around a small and large gap at a forested alpine site in the Swiss Alps during the 2015 and 2016 snowmelt seasons (March-April). Canopy surface temperatures within the small gap were within 2-3°C of measured reference air temperature. Vertical and horizontal variations in canopy surface temperatures were greatest around the large gap, varying up to 18°C above measured reference air temperature during clear-sky days. Nighttime canopy surface temperatures around the study site were up to 3°C cooler than reference air temperature. These measurements were used to develop a simple parameterization for correcting reference air temperature for elevated canopy surface temperatures during (1) nighttime conditions (subcanopy shortwave radiation is 0 W m-2) and (2) periods of increased subcanopy shortwave radiation >400 W m-2 representing penetration of shortwave radiation through the canopy. Subcanopy shortwave and longwave radiation collected at a single point in the subcanopy over a 24 h clear-sky period was used to calculate a nighttime bulk offset of 3°C for scenario 1 and develop a multiple linear regression model for scenario 2 using reference air temperature and subcanopy shortwave radiation to predict canopy surface temperature with a root-mean-square error (RMSE) of 0.7°C. Outside of these two scenarios, reference air temperature was used to predict subcanopy incoming longwave radiation. Modeling at 20 radiometer locations throughout two snowmelt seasons using these parameterizations reduced the mean bias and RMSE to below 10 W m s-2 at all locations. © 2017. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/62764
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Department of Geography, School for Engineering and Environment Northumbria University Newcastle Upon Tyne UK; WSL Institute for Snow and Avalanche Research SLF Davos Dorf Switzerland
Recommended Citation:
Webster C.,Rutter N.,Jonas T.. Improving representation of canopy temperatures for modeling subcanopy incoming longwave radiation to the snow surface[J]. Journal of Geophysical Research: Atmospheres,2017-01-01