气候变化领域集成服务门户(CCPortal): Turbulence in the stratified boundary layer under ice: Observations from Lake Baikal and a new similarity model

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DOI	10.5194/hess-24-1691-2020
	Turbulence in the stratified boundary layer under ice: Observations from Lake Baikal and a new similarity model
	Kirillin G.; Aslamov I.; Kozlov V.; Zdorovennov R.; Granin N.
发表日期	2020
ISSN	1027-5606
起始页码	1691
结束页码	1708
卷号	24 期号:4
英文摘要	Seasonal ice cover on lakes and polar seas creates seasonally developing boundary layer at the ice base with specific features: fixed temperature at the solid boundary and stable density stratification beneath. Turbulent transport in the boundary layer determines the ice growth and melting conditions at the ice-water interface, especially in large lakes and marginal seas, where large-scale water circulation can produce highly variable mixing conditions. Since the boundary mixing under ice is difficult to measure, existing models of ice cover dynamics usually neglect or parameterize it in a very simplistic form. We present the first detailed observations on mixing under ice of Lake Baikal, obtained with the help of advanced acoustic methods. The dissipation rate of the turbulent kinetic energy (TKE) was derived from correlations (structure functions) of current velocities within the boundary layer. The range of the dissipation rate variability covered 2 orders of magnitude, demonstrating strongly turbulent conditions. Intensity of mixing was closely connected to the mean speeds of the large-scale under-ice currents. Mixing developed on the background of stable density (temperature) stratification, which affected the vertical structure of the boundary layer. To account for stratification effects, we propose a model of the turbulent energy budget based on the length scale incorporating the dissipation rate and the buoyancy frequency (Dougherty-Ozmidov scaling). The model agrees well with the observations and yields a scaling relationship for the ice-water heat flux as a function of the shear velocity squared. The ice-water heat fluxes in the field were the largest among all reported in lakes (up to 40 W m-2) and scaled well against the proposed relationship. The ultimate finding is that of a strong dependence of the water-ice heat flux on the shear velocity under ice. The result suggests large errors in the heat flux estimations when the traditional "bulk" approach is applied to stratified boundary layers. It also implies that under-ice currents may have much stronger effect on the ice melt than estimated by traditional models. © 2020 Author(s).
语种	英语
scopus关键词	Atmospheric thermodynamics; Boundary layer flow; Boundary layers; Budget control; Heat flux; Kinetic energy; Kinetics; Lakes; Mixing; Shear flow; Thermal stratification; Density stratification; Ice-water interfaces; Scaling relationships; Stratification effects; Stratified boundary layers; Turbulent energy budgets; Turbulent kinetic energy; Turbulent transports; Ice; buoyancy; energy budget; heat flux; ice lake; kinetic energy; melting; mixing; model test; seasonality; stratification; turbulent boundary layer; Lake Baikal; Russian Federation
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159448
作者单位	Kirillin, G., Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Aslamov, I., Department of Hydrology and Hydrophysics, Limnological Institute, Siberian Branch of Russian Academy of Sciences, Irkutsk, Russian Federation; Kozlov, V., Institute for System Dynamics and Control Theory, Siberian Branch of Russian Academy of Science, Irkutsk, Russian Federation; Zdorovennov, R., Northern Water Problems Institute (NWPI), Karelian Research Center, Russian Academy of Sciences, Petrozavodsk, Russian Federation; Granin, N., Department of Hydrology and Hydrophysics, Limnological Institute, Siberian Branch of Russian Academy of Sciences, Irkutsk, Russian Federation
推荐引用方式 GB/T 7714	Kirillin G.,Aslamov I.,Kozlov V.,et al. Turbulence in the stratified boundary layer under ice: Observations from Lake Baikal and a new similarity model[J],2020,24(4).
APA	Kirillin G.,Aslamov I.,Kozlov V.,Zdorovennov R.,&Granin N..(2020).Turbulence in the stratified boundary layer under ice: Observations from Lake Baikal and a new similarity model.Hydrology and Earth System Sciences,24(4).
MLA	Kirillin G.,et al."Turbulence in the stratified boundary layer under ice: Observations from Lake Baikal and a new similarity model".Hydrology and Earth System Sciences 24.4(2020).