growth_rate_curve {ShellChron}

Function that creates a skewed sinusoidal growth rate (GR) curve from a list of parameters

Description

Takes the specified parameters for amplitude, period, phase, average value and skewness factor as well as the number of years specified and the time interval. It then creates a skewed sinusoid based on the boundary conditions. The skewness factor (G_skw) determines whether the sinusoid is skewed towards the front (G_skw < 50) or the back of the annual peak in growth rate (G_skw > 50). Used as intermediate step during iterative modeling.

Usage

growth_rate_curve(G_par, years = 1, t_int = 1)

Arguments

G_par

List of four parameters describing (in order) amplitude (G_amp; in micrometer/day), period (G_per; in days), phase (G_pha in day of the year), average growth rate (G_av; in micrometer/day) and the skewness factor (G_skw between 0 and 100)

years

Length of the preferred sinusoid in number of years (defaults to 1)

t_int

Time interval of sinusoidal record (in days)

Value

A matrix containing columns for time (in days) and GR (in micrometer/day)

References

doi: 10.1016/j.palaeo.2017.09.034

Examples

# Set parameters
G_amp <- 20
G_per <- 365
G_pha <- 100
G_av <- 15
G_skw <- 70
G_par <- c(G_amp, G_per, G_pha, G_av, G_skw)
# Run GR model function
GR <- growth_rate_curve(G_par, 1, 1)