气候变化领域集成服务门户(CCPortal): A multi-season investigation of glacier surface roughness lengths through in situ and remote observation

CCPortal

DOI	10.5194/tc-13-1051-2019
	A multi-season investigation of glacier surface roughness lengths through in situ and remote observation
	Fitzpatrick N.; Radić V.; Menounos B.
发表日期	2019
ISSN	19940416
EISSN	13
起始页码	1051
结束页码	1071
卷号	13 期号:3
英文摘要	The roughness length values for momentum, temperature, and water vapour are key inputs to the bulk aerodynamic method for estimating turbulent heat flux. Measurements of site-specific roughness length are rare for glacier surfaces, and substantial uncertainty remains in the values and ratios commonly assumed when parameterising turbulence. Over three melt seasons, eddy covariance observations were implemented to derive the momentum and scalar roughness lengths at several locations on two mid-latitude mountain glaciers. In addition, two techniques were developed in this study for the remote estimation of momentum roughness length, utilising lidar-derived digital elevation models with a 1×1m resolution. Seasonal mean momentum roughness length values derived from eddy covariance observations at each location ranged from 0.7 to 4.5mm for ice surfaces and 0.5 to 2.4mm for snow surfaces. From one season to the next, mean momentum roughness length values over ice remained relatively consistent at a given location (0-1mm difference between seasonal mean values), while within a season, temporal variability in momentum roughness length over melting snow was found to be substantial (> an order of magnitude). The two remote techniques were able to differentiate between ice and snow cover and return momentum roughness lengths that were within 1-2mm (≪ an order of magnitude) of the in situ eddy covariance values. Changes in wind direction affected the magnitude of the momentum roughness length due to the anisotropic nature of features on a melting glacier surface. Persistence in downslope wind direction on the glacier surfaces, however, reduced the influence of this variability. Scalar roughness length values showed considerable variation (up to 2.5 orders of magnitude) between locations and seasons and no evidence of a constant ratio with momentum roughness length or each other. Of the tested estimation methods, the Andreas (1987) surface renewal model returned scalar roughness lengths closest to those derived from eddy covariance observations. Combining this scalar method with the remote techniques developed here for estimating momentum roughness length may facilitate the distributed parameterisation of turbulent heat flux over glacier surfaces without in situ measurements. © Author(s) 2019.
学科领域	detection method; eddy covariance; glacier; heat flux; ice cover; in situ measurement; mountain region; observational method; seasonal variation; snow cover; surface roughness; water vapor; wind direction
语种	英语
scopus关键词	detection method; eddy covariance; glacier; heat flux; ice cover; in situ measurement; mountain region; observational method; seasonal variation; snow cover; surface roughness; water vapor; wind direction
来源期刊	The Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/118900
作者单位	Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, V6T 1Z4, Canada; Natural Resources and Environmental Studies Institute and Geography Program, University of Northern British Columbia, Prince George, V2N 4Z9, Canada
推荐引用方式 GB/T 7714	Fitzpatrick N.,Radić V.,Menounos B.. A multi-season investigation of glacier surface roughness lengths through in situ and remote observation[J],2019,13(3).
APA	Fitzpatrick N.,Radić V.,&Menounos B..(2019).A multi-season investigation of glacier surface roughness lengths through in situ and remote observation.The Cryosphere,13(3).
MLA	Fitzpatrick N.,et al."A multi-season investigation of glacier surface roughness lengths through in situ and remote observation".The Cryosphere 13.3(2019).