sharpshootR (version 2.4)

plotDAF: Graphical Demonstration of Declining Availability Functions

Description

This function is provides a standardized approach for the visualization of "declining availability functions" (DAF) used by various water-balance simulations. The DAF is an approximation of physical constraints on plant water extraction efficiency, as a function of declining soil moisture.

Usage

plotDAF(s = c("B", "C", "D", "G"), res = 0.01, ...)
DAF.C(x, intercept = 0)
DAF.G(x, threshold = 0.75)
DAF.B(x)
DAF.D(x)

Value

nothing, function called for graphical output

AET/PET ratio in (0, 1)

AET/PET ratio in (0, 1)

AET/PET ratio in (0, 1)

AET/PET ratio in (0, 1)

Arguments

s

character, selection of declining availability function by name ('B', 'C', 'D', 'G')

res

numeric, curve resolution typically within the range of 0.01 to 0.1

...

additional arguments to a DAF (see examples)

x

ordered sequence of VWC in (0, 1)

intercept

y-intercept, use to limit the minimum AET/PET ratio, must be within (0, 1)

threshold

soil moisture fraction threshold above which AET/PET is constant. within (0, 1)

Examples

# multi-figure output
op <- par(no.readonly = TRUE)
par(mfrow = c(2, 2))

# defaults
plotDAF('C')
plotDAF('G')
plotDAF('B')
plotDAF('D')


# adjust intercept term for DAF 'C'
plotDAF('C', intercept = 0.1)
title(sub = 'intercept = 0.1', font.sub = 3)
plotDAF('C', intercept = 0.3)
title(sub = 'intercept = 0.3', font.sub = 3)

# adjust threshold term for DAF 'G'
plotDAF('G', threshold = 0.5)
title(sub = 'threshold = 0.5', font.sub = 3)
plotDAF('G', threshold = 0.9)
title(sub = 'threshold = 0.9', font.sub = 3)


# reset output device options
par(op)