Plot transfer functions

Plot the spectral transfer functions of the effects of diffusion-like smoothing and/or time uncertainty.

Usage

PlotTF(
  dtf = NULL,
  ttf = NULL,
  names = NULL,
  col = NULL,
  dtf.threshold = NULL,
  xlab = "Time period (yr)",
  ylab1 = expression(bar(G)),
  ylab2 = expression(Phi),
  xlim = c(500, 2),
  ylim1 = c(0.005, 5),
  ylim2 = c(0.2, 1.5),
  xtm = NULL,
  ytm1 = NULL,
  ytm2 = NULL,
  xtl = NULL,
  ytl1 = NULL,
  ytl2 = NULL
)

Arguments

dtf

a list of spectral objects (?spec.object) of the transfer function datasets that describe a diffusion-type smoothing process. See Details for the meaning of NULL.

ttf

as dtf but providing time uncertainty transfer functions. See Details for the meaning of NULL.

names

an optional character vector of names for the transfer function datasets. If NULL, the names of dtf and ttf are used or, if not present, default names. Provide a list of two vectors of names, if the diffusional smoothing and time uncertainty datasets differ in number, or, if they do **not** differ in number but belong to different underlying datasets.

col

a numeric or character vector of colors to use for the plotting; if NULL default colors are used.

dtf.threshold

optional critical diffusion transfer function value to plot a corresponding horizontal line and vertical lines of corresponding frequency cutoff values (omitted for NULL).

xlab

x axis label.

ylab1

y axis label for the diffusion transfer function.

ylab2

y axis label for the time uncertainty transfer function.

xlim

the x limits (x1, x2) of the plot.

ylim1

the y limits (y1, y2) of the diffusion transfer function plot.

ylim2

the y limits (y1, y2) of the time uncertainty transfer function plot.

xtm

x axis tick mark positions; if NULL computed by axis.

ytm1

y axis tick mark positions on the diffusion transfer function plot; default setting (NULL) uses c(0.01, 0.05, 0.1, 0.5, 1, 5).

ytm2

y axis tick mark positions on the time uncertainty transfer function plot; default setting (NULL) uses c(0.2, 0.4, 0.6, 0.8, 1, 1.2).

xtl

x axis tick mark labels; if NULL determined automatically from xtm, else it must be a vector of labels of the same length as xtm.

ytl1

y axis tick mark labels on the diffusion transfer function plot; if NULL determined automatically from ytm1, else it must be a vector of labels of the same length as ytm1.

ytl2

as ytl1 for the y axis on the time uncertainty transfer function plot.

Details

You can plot only transfer functions describing diffusion-like smoothing processes by supplying the respective data to the dtf parameter and leaving the ttf parameter as NULL, or vice versa for plotting only time uncertainty transfer functions. Supplying both parameters will plot the supplied diffusional smoothing as well as time uncertainty transfer functions (which can differ in number) on a single plot with a shared x axis. Leaving both the dtf and ttf parameters as NULL (the default) will plot the firn diffusion and time uncertainty transfer functions that are provided with the proxysnr package, which corresponds to Figure B1 in Münch and Laepple (2018).

References

Münch, T. and Laepple, T.: What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores? Clim. Past, 14, 2053–2070, https://doi.org/10.5194/cp-14-2053-2018, 2018.

See also

spec.object for the definition of a proxysnr spectral object.

Author

Thomas Münch

Examples

# Plot Figure B1 in Münch and Laepple (2018), i.e. the used transfer
# functions to correct the DML and WAIS isotope spectra:

PlotTF(names = c("DML1", "DML2", "WAIS"), dtf.threshold = 0.5,
       col = c("black", "firebrick", "dodgerblue"))