abstract: program nudges the Fourier coefficients of forecasted run ("fcst data") with those of reanalysis (or other external) run (called "base data"). program starts with the conversion of spectrum base data to fourier series. this conversion is taken place in every 6 hours (nesthour). the base data is linearly interpolated for the time in between. the spectra of fcst data are also converted to fourier series. two kinds of fourier series are nudged with a weighting constant as, fnew=(1/(a+1))*(fold+a*fbase) for those with longer wavelength than lnest (e.g. 1000km) (for those with shorter, a=0). a can be variable, too (attenuating function). all of the variables, t,q,u,v,ps,gz can be nudged, but practically, ps,u,v and t should be nudged. instead, zonal q (the first coefficient of the fourier series) is replacable to that of the base data. default setting: u,v,t,ps : nudging q : zonal average replace n-scale : 2000 km n-weight : attenuating function (indaa=1)
./install --model=gsm --enable-gsmdamp
1. obtain sources
cvs co src/fcst/gloopn.F src/fcst/basefnam.F src/fcst/gsmstep.F
2. make a binary.
cd gsm ./configure-model --enable-gsmdamp cd src/fcst # edit and change parameters (lnest, aa) if necessary. make clean make
3. Get re-analysis data (sigma-level data).
sftp dataman@tsuzumi.ucsd.edu # get appropriate files
4. Change resolution (e.g. T62->T248) and save as "base.YYYYMMDDHH"
in shell script, for example,
export INPUT_RESOLUTION=t62k28 SCN=/home/work5/kei/GSM248/libs/etc/scnvrt CHGR=/home/work5/kei/GSM248/gruns/runscr/chgr INFILE=${INDIR}/sig.anl.${YEAR}${MONTH}${DAY}${TIME}.ieee TMPBASE=tmp.base OUTFILE=${OUTDIR}/base.${YEAR}${MONTH}${DAY}${TIME} TMPFILE=tmp.sig ${SCN} gsm osu1 62:192:94:28 -1:-1:-1:-1:-1 ieee:bin ${INFILE}:dummy ${TMPBASE}:dummy ${CHGR} ${TMPBASE} dummy ${OUTFILE} dummy osu1
5. modify the main script as necessary and execute.