气候变化领域集成服务门户(CCPortal): Evaluation of different methods to model near-surface turbulent fluxes for a mountain glacier in the Cariboo Mountains, BC, Canada

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DOI	10.5194/tc-11-2897-2017
	Evaluation of different methods to model near-surface turbulent fluxes for a mountain glacier in the Cariboo Mountains, BC, Canada
	Radic V.; Menounos B.; Shea J.; Fitzpatrick N.; Tessema M.A.; Déry S.J.
发表日期	2017
ISSN	19940416
卷号	11 期号:6
英文摘要	As part of surface energy balance models used to simulate glacier melting, choosing parameterizations to adequately estimate turbulent heat fluxes is extremely challenging. This study aims to evaluate a set of four aerodynamic bulk methods (labeled as C methods), commonly used to estimate turbulent heat fluxes for a sloped glacier surface, and two less commonly used bulk methods developed from katabatic flow models. The C methods differ in their parameterizations of the bulk exchange coefficient that relates the fluxes to the near-surface measurements of mean wind speed, air temperature, and humidity. The methods' performance in simulating 30â min sensible- A nd latent-heat fluxes is evaluated against the measured fluxes from an open-path eddy-covariance (OPEC) method. The evaluation is performed at a point scale of a mountain glacier, using one-level meteorological and OPEC observations from multi-day periods in the 2010 and 2012 summer seasons. The analysis of the two independent seasons yielded the same key findings, which include the following: First, the bulk method, with or without the commonly used Monin-Obukhov (M-O) stability functions, overestimates the turbulent heat fluxes over the observational period, mainly due to a substantial overestimation of the friction velocity. This overestimation is most pronounced during the katabatic flow conditions, corroborating the previous findings that the M-O theory works poorly in the presence of a low wind speed maximum. Second, the method based on a katabatic flow model (labeled as the K<>Int<> method) outperforms any C method in simulating the friction velocity; however, the C methods outperform the K<>Int<> method in simulating the sensible-heat fluxes. Third, the best overall performance is given by a hybrid method, which combines the K<>Int<> approach with the C method; i.e., it parameterizes eddy viscosity differently than eddy diffusivity. An error analysis reveals that the uncertainties in the measured meteorological variables and the roughness lengths produce errors in the modeled fluxes that are smaller than the differences between the modeled and observed fluxes. This implies that further advances will require improvement to model theory rather than better measurements of input variables. Further data from different glaciers are needed to investigate any universality of these findings. © 2017 Author(s).
学科领域	aerodynamics; air temperature; eddy covariance; energy balance; glacier; humidity; katabatic flow; Monin-Obukhov theory; parameterization; sensible heat flux; surface energy; turbulent flow; wind velocity; Cariboo Mountains; Columbia Mountains
语种	英语
scopus关键词	aerodynamics; air temperature; eddy covariance; energy balance; glacier; humidity; katabatic flow; Monin-Obukhov theory; parameterization; sensible heat flux; surface energy; turbulent flow; wind velocity; Cariboo Mountains; Columbia Mountains
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119292
作者单位	Earth Ocean and Atmospheric Sciences Department (EOAS), University of British Columbia, Vancouver, Canada; Natural Resources and Environmental Studies Institute and Geography Program, University of Northern British Columbia, Prince George, Canada; International Centre for Integrated Mountain Development (ICIMOD), Kathmandu, Nepal; Centre for Hydrology, University of Saskatchewan, Saskatoon, Canada; Natural Resources and Environmental Studies Institute, Environmental Science and Engineering Program, University of Northern British Columbia, Prince George, Canada
推荐引用方式 GB/T 7714	Radic V.,Menounos B.,Shea J.,et al. Evaluation of different methods to model near-surface turbulent fluxes for a mountain glacier in the Cariboo Mountains, BC, Canada[J],2017,11(6).
APA	Radic V.,Menounos B.,Shea J.,Fitzpatrick N.,Tessema M.A.,&Déry S.J..(2017).Evaluation of different methods to model near-surface turbulent fluxes for a mountain glacier in the Cariboo Mountains, BC, Canada.Cryosphere,11(6).
MLA	Radic V.,et al."Evaluation of different methods to model near-surface turbulent fluxes for a mountain glacier in the Cariboo Mountains, BC, Canada".Cryosphere 11.6(2017).