R: Univariate bias correction via quantile delta mapping

QDM {MBC}

R Documentation

Univariate bias correction via quantile delta mapping

Description

Univariate bias correction based on the quantile delta mapping QDM version of the quantile mapping algorithm from Cannon et al. (2015). QDM constrains model-projected changes in quantiles to be preserved following bias correction by quantile mapping.

Usage

QDM(o.c, m.c, m.p, ratio=FALSE, trace=0.05, trace.calc=0.5*trace,
    jitter.factor=0, n.tau=NULL, ratio.max=2,
    ratio.max.trace=10*trace, ECBC=FALSE, ties='first',
    subsample=NULL, pp.type=7)

Arguments

`o.c`	vector of observed samples during the calibration period.
`m.c`	vector of model outputs during the calibration period.
`m.p`	vector of model outputs during the projected period.
`ratio`	logical value indicating if samples are of a ratio quantity (e.g., precipitation).
`trace`	numeric value indicating the threshold below which values of a ratio quantity (e.g., `ratio=TRUE`) should be considered exact zeros.
`trace.calc`	numeric value of a threshold used internally when handling of exact zeros; defaults to one half of `trace`.
`jitter.factor`	optional strength of jittering to be applied when quantities are quantized.
`n.tau`	number of quantiles used in the quantile mapping; `NULL` equals the length of the `m.p` series.
`ratio.max`	numeric value indicating the maximum proportional change allowed for ratio quantities below the `ratio.max.trace` threshold.
`ratio.max.trace`	numeric value of a trace threshold used to constrain the proportional change in ratio quantities to `ratio.max`; defaults to ten times `trace`.
`ECBC`	logical value indicating whether `mhat.p` outputs should be ordered according to `o.c` ranks, i.e., as in the empirical copula-bias correction (ECBC) algorithm.
`ties`	method used to handle ties when calculating ordinal ranks.
`subsample`	use `subsample` draws of size `n.tau` to calculate empirical quantiles; if `NULL`, calculate normally.
`pp.type`	type of plotting position used in `quantile`.

Value

a list of with elements consisting of:

`mhat.c`	vector of bias corrected `m.c` values for the calibration period.
`mhat.p`	vector of bias corrected `m.p` values for the projection period.

References