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Reformatting files to AeroCom/HTAP standards
The AeroCom standard is described in the section “submitting to the AeroCom database”. https://wiki.met.no/aerocom/data_submission
Below simple nco commands are listed which can be of help to reformat.
Another set of tools is under development and can be accessed here: https://github.com/metno/aerocom-data-correction-tools
Format can be checked with a CF checker, eg: http://cf-checker.met.no/upload
How to remind me of nco commands
Just type the command without arguments on a command line
How to rename variables
ncrename -v oldvar,newvar in.nc
How to add an attribute
ncatted -a experiment,newvar,a,c,"BASE" in.nc
Split files per variable
rename dimension
ncrename -O -d LATITUDE,y temp.nc
sums
ncap2 -O -s "LOAD_BCPOM[time,x,y]=LOAD_BC+LOAD_POM" ${file} ${file}
compute vertical integrals
rm dummy.nc ncwa -O -v AERH2O3D_AER -a z -y ttl ${file} dummy.nc ncrename -O -v AERH2O3D_AER,AERH2O_AER dummy.nc ncks -F -A -v AERH2O_AER dummy.nc ${file}
add variable to file
ncks -F -A -v AIRE temp.nc ${file}
make the time dimension unlimited
ncecat -O $file $file ncpdq -O -a time,record $file $file ncwa -O -a record $file $file ncpdq -O -a time,y,x $file $file
turn z
ncpdq -O -a -z $file $file
create yearly mean file
from 12 months in one file
orgfile=MM_${model}.an${an}.mALLYEAR_an.nc ncwa -F -O -a time ${file} ${orgfile}
calculate yearly average
fom 12 files each containing 1 month
ncra -F -O modis_2000??.nc ${yearfile}
create record dimension
ncecat -O $file $file
delete useless record dimension
ncwa -O -a record $file $file
turn lat to have right order
with interpolated files
ncpdq -O -a "-y" $file $file
Shift left and right hemispheres
file1=aire_1.nc ncks -h -F -O -d x,1,180 $file $file1 file2=aire_2.nc ncks -h -F -O -d x,181,360 $file $file2 ncap -O -s "x[x]=x-360" $file2 $file2
ncrcat -O $file2 $file1 $file \rm $file1 $file2
Similar reorder of longitude
ncecat -O $file $file ncpdq -O -a x,record $file $file ncwa -O -a record $file $file
file1=DD_${model}.an${AN}.mALLYEAR_1.nc ncks -F -O -d x,1,180 $file $file1
file2=DD_${model}.an${AN}.mALLYEAR_2.nc ncks -F -O -d x,181,360 $file $file2 ncap -O -s "x[x]=x-360" $file2 $file2 ncrcat -O $file2 $file1 $file \rm $file1 $file2
ncpdq -O -a time,y,x $file $file
missing values
ncatted -O -a missing_value,$var,o,f,0 ${file} ncatted -O -a missing_value,$var,o,f,-9999 ${file}
actually better use attribute _FillValue (see http://nco.sourceforge.net)
compute monthly mean files
for IMTH in ${MTH[*]} ; do file=DD_${model}.an${AN}.m${IMTH}.nc filemean=DD_${model}.an${AN}.m${IMTH}_m.nc ncra -F -O ${file} ${filemean} done
delete attributes
ncatted -O -a ,,d,, interdummy.nc ncatted -h -a ,global,d,, interdummy.nc ncatted -h -a missing_value,,d,, interdummy.nc