New parameters
Mass density of air
At the moment almost all of the chemical and aerosol species we disseminate and archive are expressed as mass mixing ratios. While this might be sufficient for most of the users, some would prefer to use mass concentration values.
The conversion formula is simple and we are now providing air density as a new parameter to the CAMS global dissemination streams (CAMS_NREALTIME/CAMS_GLOBAL). The new parameter is available on pressure and model levels in both GRIB and NetCDF format. The new files are named as follows:
z_cams_c_ecmf_20180425000000_prod_an_ml_000_den.grib z_cams_c_ecmf_20180425000000_prod_an_ml_000_den.nc z_cams_c_ecmf_20180425000000_prod_an_pl_000_den.grib z_cams_c_ecmf_20180425000000_prod_an_pl_000_den.nc ... z_cams_c_ecmf_20180425000000_prod_fc_ml_012_den.grib z_cams_c_ecmf_20180425000000_prod_fc_ml_012_den.nc z_cams_c_ecmf_20180425000000_prod_fc_pl_012_den.grib z_cams_c_ecmf_20180425000000_prod_fc_pl_012_den.nc ...
Computation scripts
To compute mass concentration you can use the scripts below.
Compute mass concentration of a chemical species on pressure level from NetCDF output
compute_nc_concentration.sh
#!/bin/sh
set -ex
module load cdo
DATADIR=/path-to-datadir
LEVEL=1000 # select pressure level
PARAM=co # select parameter
# extract single level field
cdo -sellevel,${LEVEL} ${DATADIR}/z_cams_c_ecmf_20180425000000_prod_fc_pl_012_${PARAM}.nc ${PARAM}_mmr_${LEVEL}.nc
cdo -sellevel,${LEVEL} ${DATADIR}/z_cams_c_ecmf_20180425000000_prod_fc_pl_012_den.nc den_${LEVEL}.nc
# unpack NetCDF data
cdo -b f32 copy ${PARAM}_mmr_${LEVEL}.nc ${PARAM}_mmr_${LEVEL}_32.nc
cdo -b f32 copy den_${LEVEL}.nc den_${LEVEL}_32.nc
# compute concentration = mmr * air_density
cdo mul ${PARAM}_mmr_${LEVEL}_32.nc den_${LEVEL}_32.nc ${PARAM}_conc_${LEVEL}.nc
Compute mass concentration of a chemical species on model level from GRIB file
compute_grib_concentration.sh
#!/bin/sh
set -ex
module load eccodes
module load cdo
DATADIR=/path-to-datadir
LEVEL=60 # select model level
PARAM=no2 # select parameter
# extract single level field
grib_copy -w level=${LEVEL} ${DATADIR}/z_cams_c_ecmf_20180425000000_prod_fc_pl_012_${PARAM}.grib ${PARAM}_mmr_${LEVEL}.grib
grib_copy -w level=${LEVEL} ${DATADIR}/z_cams_c_ecmf_20180425000000_prod_fc_pl_012_den.grib den_${LEVEL}.grib
# compute concentration = mmr * air_density
cdo mul ${PARAM}_mmr_${LEVEL}.grib den_${LEVEL}.grib ${PARAM}_conc_${LEVEL}.grib
A new near-surface data service
TODO: Describe lowest model level service
New aerosol parameters
TODO: Should we add a list of new parameters that are now properly archived? Perhaps someone might be interested