Vertical diffusion in small stratified lake: Data and error analysis
Water temperature profiles were measured at 2-min intervals in a stratified temperate lake with a surface area of 0.06 sq km and a maximum depth of 10 m from May 7 to August 9, 1989. The data were used to calculate the vertical eddy diffusion coefficient K sub z in the hypolimnion. The depth was representative of a large number of lakes in the north central United States. K sub z was calculated over time intervals of 1 to 15 days and varied from 0.001 to 0.1 sq cm/s. A numerical model was developed for heat conduction in the sediments, and heat flux between water and sediments was incorporated into the relationship from which eddy diffusivity was estimated. Heat flux between water and lake sediments, a term commonly neglected, was found to be important in the K sub x estimation. K sub z values were related to stratification stability as measured by the Brunt-Vaisala frequency N using Welander's expression of the form K sub z = a(N(2+))(b+). The longest time interval (15 days) and the smallest depth increment (1 m) used in the study were found to give the best K sub z estimation.
- Research Organization:
- Minnesota Univ., Minneapolis, MN (United States). St. Anthony Falls Hydraulic Lab.
- OSTI ID:
- 6660270
- Report Number(s):
- PB-93-149185/XAB; CNN: EPA-R-816230-01-0
- Resource Relation:
- Other Information: Pub. in Jnl. of Hydraulic Engineering, Vol. 117, No. 10, 1353-1369(Oct 1991)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LAKES
TEMPERATURE GRADIENTS
DEPTH
DIAGRAMS
DIFFUSION
FORECASTING
HEAT FLUX
HEAT TRANSFER
LIMNOLOGY
MATHEMATICAL MODELS
MINNESOTA
NUMERICAL SOLUTION
SEDIMENTS
STABILITY
STRATIFICATION
THERMAL CONDUCTIVITY
USA
DEVELOPED COUNTRIES
DIMENSIONS
ENERGY TRANSFER
NORTH AMERICA
PHYSICAL PROPERTIES
SURFACE WATERS
THERMODYNAMIC PROPERTIES
540310* - Environment
Aquatic- Basic Studies- (1990-)