Clean up nc and grb dirs before converting

ERAIN_SFC12_MM/util/convert_to_netcdf.sh

@@ -5,12 +5,12 @@ function convert_grb_to_netcdf {
     nc_file="$(echo ${grb_file} | rev | cut -d. -f2- | rev)".nc
     tmp_nc_file=${nc_file}_tmp
     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}
 }
 export -f convert_grb_to_netcdf
 
+rm -f data/grb/* data/nc/*
 find data -iname \*.grb -print0 | \
     xargs -0 -n1 -P4 -I {} bash -c "convert_grb_to_netcdf {}"