Clim {s2dv}

Compute Bias Corrected Climatologies

Description

This function computes per-pair climatologies for the experimental and observational data using one of the following methods:

1. per-pair method (Garcia-Serrano and Doblas-Reyes, CD, 2012 https://doi.org/10.1007/s00382-012-1413-1)

2. Kharin method (Kharin et al, GRL, 2012 https://doi.org/10.1029/2012GL052647)

3. Fuckar method (Fuckar et al, GRL, 2014 https://doi.org/10.1002/2014GL060815)

Per-pair climatology means that only the startdates covered by the whole experiments/observational dataset will be used. In other words, the startdates which are not all available along 'dat_dim' dimension of both the 'exp' and 'obs' are excluded when computing the climatologies. Kharin method is the linear trend bias correction method, and Fuckar method is the initial condition bias correction method. The two methods both do the per-pair correction beforehand.

Usage

Clim(
  exp,
  obs,
  time_dim = "sdate",
  dat_dim = c("dataset", "member"),
  method = "clim",
  ftime_dim = "ftime",
  memb = TRUE,
  memb_dim = "member",
  na.rm = TRUE,
  ncores = NULL
)

Arguments

exp

A named numeric array of experimental data with at least dimension 'time_dim'.

obs

A named numeric array of observational data that has the same dimension as 'exp' except 'dat_dim'.

time_dim

A character string indicating the name of dimension along which the climatologies are computed. The default value is 'sdate'.

dat_dim

A character vector indicating the name of the dataset and member dimensions. If data at one startdate (i.e., 'time_dim') are not complete along 'dat_dim', this startdate along 'dat_dim' will be discarded. If there is no dataset dimension, it can be NULL, however, it will be more efficient to simply use mean() to do the calculation. The default value is "c('dataset', 'member')".

method

A character string indicating the method to be used. The options include 'clim' (per-pair method), 'kharin' (Kharin method), and 'NDV' (Fuckar method). The default value is 'clim'.

ftime_dim

A character string indicating the name of forecast time dimension. Only used when method = 'NDV'. The default value is 'ftime'.

memb

A logical value indicating whether to remain 'memb_dim' dimension (TRUE) or do ensemble mean over 'memb_dim' (FALSE). The default value is TRUE.

memb_dim

A character string indicating the name of the member dimension. Only used when parameter 'memb' is FALSE. It must be one element in 'dat_dim'. The default value is 'member'.

na.rm

A logical value indicating whether to remove NA values along 'time_dim' when calculating climatology (TRUE) or return NA if there is NA along 'time_dim' (FALSE). The default value is TRUE.

ncores

An integer indicating the number of cores to use for parallel computation. The default value is NULL.

Value

A list of 2:

$clim_exp

A numeric array with the same dimensions as parameter 'exp' but dimension 'time_dim' is moved to the first position. If parameter 'method' is 'clim', dimension 'time_dim' is removed. If parameter 'memb' is FALSE, dimension 'memb_dim' is also removed.

$clim_obs

A numeric array with the same dimensions as parameter 'obs' except dimension 'time_dim' is removed. If parameter 'memb' is FALSE, dimension 'memb_dim' is also removed.

Examples

# Load sample data as in Load() example:
example(Load)
clim <- Clim(sampleData$mod, sampleData$obs)
clim2 <- Clim(sampleData$mod, sampleData$obs, method = 'kharin', memb = FALSE)
## Not run: 
PlotClim(clim$clim_exp, clim$clim_obs, 
        toptitle = paste('sea surface temperature climatologies'), 
        ytitle = 'K', monini = 11, listexp = c('CMIP5 IC3'), 
        listobs = c('ERSST'), biglab = FALSE)

## End(Not run)