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",failure.action=NULL,
          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.
failure.action If stepwise screening in DS fails to select any variables, then call the function specified by a character string, unless set to NULL.

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 2.2-15 Index]