R/build_gsod_forcing_data.R

In EcoHydRology: A Community Modeling Foundation for EcoHydrology

build_gsod_forcing_data <-
function(){
  tmpdir=readline("Please enter a temp directory where you stored the *.op.gz datafiles? \n")
  files=dir(tmpdir,"*.op.gz",full.names=T)
  start_year=min(substr(files,nchar(files)-9,nchar(files)-6))
  end_year=max(substr(files,nchar(files)-9,nchar(files)-6))
  alldates=data.frame(fdate=seq(from=as.Date(paste(start_year,"-01-01",sep="")), to=as.Date(paste(end_year,"-12-31",sep="")), by=1))

  stn=matrix()
  tmin=matrix()
  tmax=matrix()
  ppt=matrix()
  fdate=matrix()
  for (tmpfile in files){
#
# There is more data in this dataset we can extract later as we need it.
#
#
        tmpstring<-grep("MAX",readLines( gzfile(tmpfile)),value=TRUE,invert=TRUE)
        stn<-c(stn,as.numeric(as.character(substring(tmpstring,1,5))))
        tmax<-c(tmax,as.numeric(as.character(substring(tmpstring,103,108))))
        tmin<-c(tmin,as.numeric(as.character(substring(tmpstring,111,116))))
        ppt<-c(ppt,as.numeric(as.character(substring(tmpstring,119,123))))
        fdate<-c(fdate,as.Date(yearmoda<-substring(tmpstring,15,22),"%Y%m%d"))
  }

  stn<-as.numeric(stn)
  ppt<-as.numeric(ppt)
  tmax<-as.numeric(tmax)
  tmin<-as.numeric(tmin)
  fdate<-as.Date(as.numeric(fdate), origin="1970-01-01")
  forcing=data.frame(stn=stn,ppt=ppt,tmax=tmax,tmin=tmin, fdate=as.Date(fdate))
  forcing=na.omit(forcing)
  forcing=merge(alldates,forcing,all=TRUE)

  forcing$ppt_mm <- forcing$ppt*25.4
  forcing$tmax_C <- (forcing$tmax-32) * 5/9
  forcing$tmin_C <- (forcing$tmin-32) * 5/9
  forcing$tavg_C <-(forcing$tmin_C+forcing$tmax_C)/2
  forcing$ppt_mm[forcing$ppt_mm > 999]=0.0
  return(forcing)
}