uStar {rLakeAnalyzer}

Calculates the water friction velocity, uStar

Description

uStar is the water friction velocity due to wind stress at the lake surface, it is calculated following the methods of Imberger (1985) as a function of the shear stress of air (Fischer et al., 1979), drag coefficient for momentum (Hicks, 1972), and a dimensionless constant (von Karman constant) that decribes the logarithmic velocity profile at the air-water interface

Usage

uStar(wndSpeed, wndHeight, averageEpiDense)

Arguments

wndSpeed

a numeric vector of wind speed in m s-1

wndHeight

a numeric vector of wind measurement height in m

averageEpiDense

a numeric vector of epilimnion density in kg m-3

Value

a numeric vector of uStar

References

Hicks, B.B., 1972. A procedure for the formulation of bulk transfer coefficients over water bodies of different sizes. Boundary-Layer Meterology 3: 201-213.

Amorocho, J., DeVries, J.J., 1980. A new evaluation of the wind stress coefficient over water surfaces. Journal of Geophysical Research 85: 433-442.

Fischer, H.B., List, E.J., Koh, R.C.Y., Imberger, J., Brooks, N.H., 1979. Mixing in inland and coastal waters. Academic Press.

Imberger, J., 1985. The diurnal mixed layer. Limnology and Oceanography 30: 737-770.

See Also

ts.uStar layer.density

Examples

  wndSpeed  <- c(5.1,6.3,6.3,5.2,7,7.2)
  wndHeight	<-	2
  averageEpiDense	<- c(14,15,14.2,13,12,12)

  cat('uStar for input vector is: ')
  cat(uStar(wndSpeed,wndHeight,averageEpiDense))