http://presentations.copernicus.org/EGU2014-5768_presentation.pdf

http://rcg.gvc.gu.se/edu/esd.pdf

First you have to convert  station data (Observed data) into 'zoo' series and add attributes as required by 'esd' package.

You also need GCM/reanalysis data in netCDF(nc) format.

Now select a domain for  by subsetting the global GCM/reanalysisdata.

Let y be the observed data and z be the global GCM/reanalysis data

>x=subset(z,is=list(lon=c(lon1,lon2),lat=c(lat1,lat2)))

# for example if you select a domain 60-70 degree E and 20-30 degree N

then lon1=60,lon2=70; lat1=20,lat2=30

>eof=EOF(x) # Empirical orthogonal function (EOF) analysis

>ds=DS(y,eof) # ds is the downscaled data