Merge branch 'update-erain-timeaxis' into 'master'

Let CDO create a relative time axis

See merge request !9

ERAIN_SFC12_MM/util/convert_to_netcdf.sh

@@ -4,7 +4,8 @@ function convert_grb_to_netcdf {
     grb_file=$1
     nc_file="$(echo ${grb_file} | rev | cut -d. -f2- | rev)".nc
     tmp_nc_file=${nc_file}_tmp
-    cdo -t ecmwf -f nc -copy ${grb_file} ${tmp_nc_file}
+    cdo -r -t ecmwf -f nc -copy ${grb_file} ${tmp_nc_file}
+    rm -f ${nc_file}
     nccopy -7 -d1 -s ${tmp_nc_file} ${nc_file}
     rm -f ${tmp_nc_file}
 }