ProxiesAttractor: Computing two dinamical proxies of the attractor.

In CSTools: Assessing Skill of Climate Forecasts on Seasonal-to-Decadal Timescales

Computing two dinamical proxies of the attractor.

Description

This function computes two dinamical proxies of the attractor: The local dimension (d) and the inverse of the persistence (theta). These two parameters will be used as a condition for the computation of dynamical scores to measure predictability and to compute bias correction conditioned by the dynamics with the function DynBiasCorrection. Funtion based on the matlab code ([e-mail]) used in:

Usage

ProxiesAttractor(data, quanti, ncores = NULL)

Arguments

data	A multidimensional array with named dimensions to create the attractor. It requires a temporal dimension named 'time' and spatial dimensions called 'lat' and 'lon', or 'latitude' and 'longitude' or 'grid'.
quanti	A number lower than 1 indicating the quantile to perform the computation of local dimension and theta
ncores	The number of cores to use in parallel computation.

Value

dim and theta

Author(s)

Carmen Alvarez-Castro, [e-mail]

Maria M. Chaves-Montero, [e-mail]

Veronica Torralba, [e-mail]

Davide Faranda, [e-mail]

References

Faranda, D., Alvarez-Castro, M.C., Messori, G., Rodriguez, D., and Yiou, P. (2019). The hammam effect or how a warm ocean enhances large scale atmospheric predictability. Nature Communications, 10(1), 1316. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1038/s41467-019-09305-8")}"

Faranda, D., Gabriele Messori and Pascal Yiou. (2017). Dynamical proxies of North Atlantic predictability and extremes. Scientific Reports, 7-41278, 2017.

Examples

# Example 1: Computing the attractor using simple data
# Creating an example of matrix data(time,grids):
mat <- array(rnorm(36 * 40), c(time = 36, grid = 40)) 
qm <- 0.90 # imposing a threshold
Attractor <- ProxiesAttractor(data = mat, quanti = qm)
# to plot the result
time = c(1:length(Attractor$theta))
plot(time, Attractor$dim, xlab = 'time', ylab = 'd',
    main = 'local dimension', type = 'l')

CSTools documentation built on Oct. 20, 2023, 5:10 p.m.