lake.number: Calculate Lake Number

Description

The Lake Number, defined by Imberger and Patterson (1990), has been used to describe processes relevant to the internal mixing of lakes induced by wind forcings. Lower values of Lake Number represent a higher potential for increased diapycnal mixing, which increases the vertical flux of mass and energy across the metalimnion through the action of non-linear internal waves. Lake Number is a dimensionless index.

Lake Number has been used, for example, to estimate the flux of oxygen across the thermocline in a small lake (Robertson and Imberger, 1994), and to explain the magnitude of the vertical flux of ammonium in a lake (Romero et al., 1998).

Usage

lake.number(bthA, bthD, uStar, St, metaT, metaB, averageHypoDense)

Arguments

bthA

a numeric vector of cross sectional areas (m2) corresponding to bthD depths, hypsographic areas

bthD

a numeric vector of depths (m) which correspond to areal measures in bthA, hypsographic depths

uStar

a numeric array of u* (m/s), water friction velocity due to wind stress

a numeric array of Schmidt stability (J/m2), as defined by Idso 1973

metaT

a numeric array of the top of the metalimnion depth (m from the surface)

metaB

a numeric array of the bottom of the metalimnion depth (m from the surface)

averageHypoDense

a numeric array of the average density of the hypolimnion (kg/m3)

Value

A numeric vector of Lake Number [dimensionless]

References

Imberger, J., Patterson, J.C., 1990. Physical limnology. Advances in Applied Mechanics 27, 303-475.

Idso, S.B., 1973. On the concept of lake stability. Limnology and Oceanography 18, 681-683.

Examples

Run this code

# NOT RUN {
	bthA	<-	c(1000,900,864,820,200,10)
	bthD	<-	c(0,2.3,2.5,4.2,5.8,7)
	uStar	<-	c(0.0032,0.0024)
	St	<-	c(140,153)
	metaT	<-	c(1.34,1.54)
	metaB	<-	c(4.32,4.33)
	averageHypoDense	<-	c(999.3,999.32)
	cat('Lake Number for input vector is: ')
	cat(lake.number( bthA, bthD, uStar, St, metaT, metaB, averageHypoDense) )

# }