7. Input Datasets

Input datasets are required to run the model and differ depending on the configuration used. Required datasets include initial conditions, topography, emissions, lower boundary conditions, soil erodibility data for dust emissions, and solar input files. In addition, meteorological data are required to run the model in specified dynamics mode. Furthermore, CAM and WACCM SC (specified chemistry), and simulations with prescribed stratospheric aerosols require prescribed input datasets that are derived from full chemistry simulations. Additional datasets include sea-surface temperatures, and prescribed land data.

The CIME infrastructure has utilities to help obtain this data on a local filesystem. The place where CIME looks for input data is specified by the variable DIN_LOC_ROOT. The datasets needed for CAM configurations are stored in namelist default files with pathnames that are relative to $DIN_LOC_ROOT. When build-namelist writes the namelist files, dataset filenames are resolved to have absolute filepaths. build-namelist also produces a file, $CASEROOT/Buildconf/cam.input_data_list, that contains all the names of the required input datasets. The case.submit script runs a CIME command

./check_input_data --download

which checks whether the required datasets exist in $DIN_LOC_ROOT, and if they do not it tries to download them from the CESM SVN input data repository. The check_input_data command may also be invoked by the user from the $CASEROOT directory. See the check_input_data documentation for more information.

This chapter presents some additional information about the required input datasets.

7.1. Emissions

All CAM, CAM-chem and WACCM configurations require surface emissions and, in most cases, external forcings (vertically distributed emissions). In the standard compsets all biomass burning emissions are at the surface. Anthropogenic emissions are mostly released at the surface, but some sectors of sulfate emissions are injected vertically. Aircraft and volcanic emissions are distributed with altitude. The standard emission files are provided separately for each sector: anthropogenic (anthro), biomass burning (bb), biogenic (bg), volcanic source and others (soil, ocean etc.), for convenience and clarity. CAM will read multiple emissions files for each compound (specified in the namelist) and sum them in the model. There are no restrictions on the filenames or the variable names within the files.

7.1.1. Emissions datasets

It is straightforward to use different emissions inventories in CAM, CAM-chem or WACCM simulations by specifying different files (in the proper format) in the namelist. A list of emissions inventories that have been used by CESM are here.

7.1.2. Species with emissions (CAM)

  • Surface (anthro, bb):

    bc_a4 , pom_a4 , num_a4 (for bc_a4 and pom_a4), SO2

  • Surface (anthro, bb, biogenic):

    SOAG

  • Vertical (extfrc):

    SO2 (aircraft, contvolcano), so4_a1 (anthro-ene, contvolcano),
so4_a2 (contvolcano), bc_a4 (aircraft), num_a1, num_a2, num_a4

7.1.3. Species with dry and wet deposition (CAM)

  • Aerosols:

    bc_a1, bc_a4, dst_a1, dst_a2, dst_a3, ncl_a1, ncl_a2, ncl_a3, num_a1,
num_a2, num_a3, num_a4, pom_a1, pom_a4, so4_a1, so4_a2, so4_a3, soa_a1,
soa_a2

  • Gas-phase:

    H2O2, H2SO4, SO2

7.1.4. Species with emissions (CAMchem/WACCM)

  • Surface (anthro, bb, other):

    NO, NH3, CO, C2H4, C2H6, C3H6, C3H8

  • Surface (anthro, bb):

    bc_a4, pom_a4, num_a4, SO2, C2H2, BIGALK, BIGENE, BENZENE, TOLUENE,
XYLENES, CH3OH, C2H5OH, CH2O, CH3CHO, CH3COCH3, MEK, HCOOH, CH3COOH,
HCN, CH3CN, IVOC, SVOC

  • Vertical:

    NO2 (aircraft), SO2 (aircraft, contvolcano, erupting volcanoes), so4_a1
(anthro-ene, contvolcano), so4_a2 (contvolcano), bc_a4 (aircraft),
num_a1, num_a2, num_a4

7.1.5. Species with dry and wet deposition (CAMChem/WACCM)

Species with dry deposition

  • Aerosols:

    bc_a1, bc_a4, dst_a1, dst_a2, dst_a3, ncl_a1, ncl_a2, ncl_a3, num_a1,
num_a2, num_a3, num_a4, pom_a1, pom_a4, so4_a1, so4_a2, so4_a3,
soa1_a1, soa1_a2, soa2_a1, soa2_a2, soa3_a1, soa3_a2, soa4_a1, soa4_a2,
soa5_a1, soa5_a2

  • Gas-phase:

    ALKNIT, ALKOOH, BENZOOH, BZOOH, C2H5OH, C2H5OOH, C3H7OOH, C6H5OOH,
CH2O, CH3CHO, CH3CN, CH3COCH3, CH3COCHO, CH3COOH, CH3COOOH, CH3OH,
CH3OOH, CO, EOOH, GLYALD, H2O2, H2SO4, HCN, HCOOH, HNO3, HO2NO2,
HONITR, HPALD, HYAC, HYDRALD, IEPOX, ISOPNITA, ISOPNITB, ISOPNO3,
ISOPNOOH, ISOPOOH, IVOC, MACROOH, MEKOOH, MPAN, NC4CH2OH, NC4CHO, NH3,
NH4, NO, NO2, NOA, NTERPOOH, O3, ONITR, PAN, PHENOOH, POOH, ROOH, SO2,
SOAG0, SOAG1, SOAG2, SOAG3, SOAG4, SVOC, TERP2OOH, TERPNIT, TERPOOH,
TERPROD1, TERPROD2, TOLOOH, XOOH, XYLENOOH, XYLOLOOH

Species with wet deposition

  • Aerosols:

    bc_a1, bc_a4, dst_a1, dst_a2, dst_a3, ncl_a1, ncl_a2, ncl_a3, num_a1,
num_a2, num_a3, num_a4, pom_a1, pom_a4, so4_a1, so4_a2, so4_a3,
soa1_a1, soa1_a2, soa2_a1, soa2_a2, soa3_a1, soa3_a2, soa4_a1, soa4_a2,
soa5_a1, soa5_a2

  • Gas-phase:

    ALKNIT, ALKOOH, BENZOOH, BRONO2, BZOOH, C2H5OH, C2H5OOH, C3H7OOH,
C6H5OOH, CH2O, CH3CHO, CH3CN, CH3COCH3, CH3COCHO, CH3COOH, CH3COOOH,
CH3OH, CH3OOH, CLONO2, COF2, COFCL, EOOH, GLYALD, H2O2, H2SO4, HBR,
HCL, HCN, HCOOH, HF, HNO3, HO2NO2, HOBR, HOCL, HONITR, HPALD, HYAC,
HYDRALD, IEPOX, ISOPNITA, ISOPNITB, ISOPNO3, ISOPNOOH, ISOPOOH, IVOC,
MACR, MACROOH, MEKOOH, MVK, NC4CH2OH, NC4CHO, NDEP, NH3, NH4, NHDEP,
NOA, NTERPOOH, ONITR, PHENOOH, POOH, ROOH, SO2, SOAG0, SOAG1, SOAG2,
SOAG3, SOAG4, SVOC, TERP2OOH, TERPNIT, TERPOOH, TERPROD1, TERPROD2,
TOLOOH, XOOH, XYLENOOH, XYLOLOOH

7.1.6. Species with biogenic emissions (CAMChem/WACCM)

Species with MEGAN emissions (CAM-chem (TS1) and WACCM (TSMLT)) are listed in drv_flds_in, and can be modified in user_nl_cam:

megan_specifier = 'ISOP = isoprene',
    'MTERP = pinene_a + carene_3 + thujene_a + 2met_styrene + cymene_p +
             cymene_o + terpinolene + bornene + fenchene_a + ocimene_al +
             pinene_b + sabinene + camphene + limonene + phellandrene_a +
             terpinene_g + terpinene_a + phellandrene_b + myrcene +
             ocimene_t_b + ocimene_c_b',
    'BCARY = caryophyllene_b + bergamotene_a + bisabolene_b +
             farnescene_b + humulene_a',
    'CH3OH = methanol',
    'C2H5OH = ethanol',
    'CH2O = formaldehyde',
    'CH3CHO = acetaldehyde',
    'CH3COOH = acetic_acid',
    'CH3COCH3 = acetone',
    'HCOOH = formic_acid',
    'HCN = hydrogen_cyanide',
    'CO = carbon_monoxide',
    'C2H6 = ethane',
    'C2H4 = ethene',
    'C3H8 = propane',
    'C3H6 = propene',
    'BIGALK = pentane + hexane + heptane + tricyclene',
    'BIGENE = butene',
    'TOLUENE = toluene'

Note

Modifications may be required for other mechanisms, see Running with interactive / prescribed biogenic emissions.

7.1.7. WACCM-X emissions

WACCM-X uses emissions relevant to middle atmosphere (MA) chemistry, consistent with those provided for the REF-C1 experiment of the IGAC/SPARC Chemistry-Climate Model Initiative (CCMI) Community Simulations.

7.2. Lower boundary datasets

A number of very long-lived chemical species have their mixing ratios specified at the surface (e.g., CO2, CH4, CFCs). The standard lower boundary condition file is provided for 1750 to 2015, and is suitable for various horizontal resolutions. This file works for all atmospheric configurations:

flbc_file =
‘$DIN_LOC_ROOT/atm/waccm/lb/LBC_17500116-20150116_CMIP6_0p5degLat_c180227.nc’

Additional files are available for the SSP scenarios.

7.3. Soil erodibility datasets

Soil erodibility maps provide a proxy for the relative ability of the soils in different regions to generate dust. The maps are input as a netcdf file, with no time dependence, and are a unitles factor for each grid box, and are interpolated to the resolution of the model within the model. They are input in the CAM, although the rest of the dust generation itself is included in CLM. The idea of the soil erodibility map comes from Ginoux et al., 2001, and the specific maps used is the geomorphic map from Zender et al., 2003a and are used in combination with the Dust Entrainment and Deposition scheme from Zender et la., 2003b, as described in Mahowald et al., 2006. The regional distribution of these values are tuned to generate a good distribution as described in Albani et al., 2014.

The file used:

soil_erod_file = '$DIN_LOC_ROOT/atm/cam/dst/dst_source2x2tunedcam6-2x2-04062017.nc’

7.4. Topography datasets

Topography files are generated with the NCAR Global Model Topography Generation Software for Unstructured Grids. See the User’s Guide for more information.

7.5. Meteorological datasets

For specified dynamics model simulations, meteorolocial analysis from the Goddard Earth Observing System Model, Version 5 (GEOS5) and the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2) data have been prepared to run CESM and WRF simulations and are available in 3 resolutions from the Research Data Archive.

These datasets and additional resolutions for GEOS5, MERRA, and MERRA2 can be found on repository, and on HSI.

7.6. Solar datasets

7.6.1. Solar irradiance

CESM2 uses solar input files provided by CMIP6. All versions of CESM2 use the solar_irrad_data_file, which provides the reconstructed spectral solar irradiance at 1 AU as the variable ssi, with units of mW m -2 nm -1.

piControl:

solar_irrad_data_file =
 '$DIN_LOC_ROOT/atm/cam/solar/SolarForcingCMIP6piControl_c160921.nc'

Historical:

solar_irrad_data_file =
 '$DIN_LOC_ROOT/atm/cam/solar/SolarForcingCMIP6_18491230-23000102_c20200615.nc'

7.6.2. WACCM solar inputs

WACCM uses 2 additional solar input files for upper-atmosphere processes:

  • solar_parms_data_file: geomagnetic parameters, including daily planetary Ap and Kp indices, and F10.7 solar radio flux.

  • epp_all_filepath: Provides epp_ion_rates variable with ion pair production rate from energetic particle precipitation, including solar protons, cosmic rays, and medium energy electrons.

The data for all three solar inputs have been combined into a single file for each time period, so that WACCM points to the same file for each.

piControl:

solar_irrad_data_file =
 '$DIN_LOC_ROOT/atm/cam/solar/SolarForcingCMIP6piControl_c160921.nc'
solar_parms_data_file =
 '$DIN_LOC_ROOT/atm/cam/solar/SolarForcingCMIP6piControl_c160921.nc'
epp_all_filepath =
 '$DIN_LOC_ROOT/atm/cam/solar/SolarForcingCMIP6piControl_c160921.nc'

Historical:

solar_irrad_data_file =
 '$DIN_LOC_ROOT/atm/cam/solar/SolarForcingCMIP6_18491230-23000102_c20200615.nc'
solar_parms_data_file =
 '$DIN_LOC_ROOT/atm/cam/solar/SolarForcingCMIP6_18491230-23000102_c20200615.nc'
epp_all_filepath =
 '$DIN_LOC_ROOT/atm/cam/solar/SolarForcingCMIP6_18491230-23000102_c20200615.nc'

7.6.3. WACCM-X solar inputs

WACCM-X uses the Naval Research Laboratory (NRL) Version 1 reconstruction for solar irradiance (Lean, ref), rather than CMIP6. Instead of the epp_all_filepath, WACCM-X uses the epp_spe_filepath, which provides ion pair production rates just for solar proton events (neglecting cosmic rays and MEE). For historical simulations, WACCM-X uses a solar_parms_data_file with 3-hour time resolution, spanning the dates April 10, 1947 to July 23, 2016.

Historical:

solar_irrad_data_file =
 '$DIN_LOC_ROOT/atm/cam/solar/spectral_irradiance_Lean_1950-2014_daily_GOME-Mg_Leap_c150623.nc'
epp_spe_filepath =
 '$DIN_LOC_ROOT/atm/waccm/solar/spes_1963-2014_c150717.nc'
solar_parms_data_file =
 '$DIN_LOC_ROOT/atm/waccm/solar/waxsolar_3hr_c170504.nc'

Constant year 2000:

solar_irrad_data_file =
 '$DIN_LOC_ROOT/atm/cam/solar/spectral_irradiance_Lean_1950-2014_daily_GOME-Mg_Leap_c150623.nc'
epp_spe_filepath =
 '$DIN_LOC_ROOT/atm/waccm/solar/spes_1963-2014_c150717.nc'
solar_parms_data_file =
 '$DIN_LOC_ROOT/atm/waccm/phot/wa_avg_c20170519.nc'