objDS {clim.pact} | R Documentation

## Objective downscaling of monthly means

### Description

'Objective' downscaling based on `DS`. The function selects region according to a correlation analysis, setting the borders where the correlation with the station series become zero. A fit to a truncated Fourier expansion is used to describe profiles of correlation coefficients in zonal and meridional directions from where the station is located.

Version 2.1-5: smallest spatial domain for objDS is set to +- 10deg N and E of the station location in order to avoid problems with dimensions if one only contains one data point (the domain becomes a line instead of a rectangle).

### Usage

    objDS(field.obs,field.gcm,station,plot=TRUE,positive=NULL,
              mon=NULL,direc="output/",cal.id=NULL,
              ldetrnd=TRUE,i.eofs=seq(1,8,by=1),ex.tag="",
              method="lm",leps=FALSE,param="t2m",
              plot.res=FALSE,plot.rate=FALSE,xtr.args="",
              swsm="step",predm="predict",lsave=FALSE,rmac=TRUE,
              silent=FALSE,qualitycontrol=TRUE,LINPACK=TRUE,wOBS=0.25)

### Arguments

`field.obs` | The gridded observation predictor `retrieve.nc`.
`field.gcm` | The climate simulation predictor `retrieve.nc`.
`station` | A climate.station object (`station.obj` or `station.obj.dm`). [e.g. from `getnacd`, `getnordklim` or `station.obj`].
`plot` | 'TRUE' produces figures.
`positive` | 'TRUE': only consider the region where correlations are positive (important for temperature predictors).
`mon` | month or season to downscale,loops though the 12 calendar months if NULL.
`direc` | name of directory inwhich the output is dumped (e.g. figures, tables).
`cal.id` | ID tag used for calibration. By default use the first field (`catFields`) for calibration.
`ldetrnd` | F for no detrending; T for removing linear trends before model calibration.
`i.eofs` | select which EOFs to include in the setp-wise screening.
`ex.tag` | Extra labelling tag for file names for experiments.
`method` | Sets the method to use for regression. Method is set to "lm" by default, but "anm" allows the incorporation of an analog model, see `anm`. "anm.weight" weights the principal components according to the eigenvalues, whereas "anm" uses unweighted series.
`leps` | 'TRUE' produces EPS figures (files).
`param` | Name of parameter (for plot labels).
`plot.res` | 'TRUE' shows statistics for residuals.
`plot.rate` | 'TRUE' shows analysis of rate-of-change.
`xtr.args` | Extra/additional arguments in the formula.
`swsm` | Step-wise screening method, default=='step'; 'none' skips stepwise sceeening.
`predm` | Prediction method, default is "predict"
`lsave` | TRUE -> saves the result on disc
`rmac` | TRUE -> subtracts (removes) the annual cycle in station data.
`silent` | TRUE -> no output to screen.
`qualitycontrol` | TRUE: perform a qualitry control consisting of comparing the smoothness of the monthly trend estimates throughout the year and repeat the downscaling with a smaller domain if adjacent trend estimates vary significantly (diff greater than 3*variance of rates).
`LINPACK` | 'TRUE': svd; 'FALSE':La.svd
`wOBS` | Used for weighting down GCM results in the common EOF analysis. The GCM results are re-scaled after the analysis.`wOBS=NULL` skips this scaling/re-scaling.

### Value

An 'objDS' object - a list of objects:

station | a 'station' object (see `getnacd`)
Jan | a 'ds' (see `DS`) object
Feb | a 'ds' object
Mar | a 'ds' object
Apr | a 'ds' object
May | a 'ds' object
Jun | a 'ds' object
Jul | a 'ds' object
Aug | a 'ds' object
Sep | a 'ds' object
Oct | a 'ds' object
Nov | a 'ds' object
Dec | a 'ds' object

### Author(s)

R.E. Benestad

### Examples

    ## Not run:
    library(clim.pact)
    oslo<-getnordklim("Oslo-Blindern")
    slp.obs <- retrieve.nc("ncep_slp.nc")         # Get gridded observations/analysis from NCEP
    slp.gcm <- retrieve.nc("EH4OPYC_B2_slp.nc")   # Get results from climate models
    ds <- objDS(field.obs=slp.obs,field.gcm=slp.gcm,station=oslo)

    t2m <- retrieve.nc("~/data/analysis/DNMI_t2m.nc")
    t2m.gcm <- retrieve.nc("~/data/mpi/mpi-gsdio_t2m.nc",
               x.rng=range(t2m$lon),y.rng=range(t2m$lat))
    ds <- objDS(field.obs=t2m,field.gcm=t2m.gcm,station=oslo)
    ## End(Not run)

[Package clim.pact version 2.2-1 Index]