&cardin – General switches

This namelist is for general CCAM options.  Below the option descriptions are grouped by categories.

Date, run length and miscellaneous

kdate_s – Start date of simulation in YYYYMMDD format

ktime_s – Start time of simulation in ZZmm format

leap – To use leap years (leap=1) or to use 365-day calendar (leap=0)

dt – Simulation time-step in seconds.  Select this link for more details dt

nwt – Standard output period in time-steps

tbave – High-frequency output period in time-steps.  Typically used for selected near surface variables (e.g., extreme rainfall).

ntau – Run length of simulation in time-steps

nmaxpr – Period of output diagnostics in time-steps

newtop – Adjust interpolated input data (e.g., nudging) for differences in orography (newtop=1)

nrungcm – Default option for soil datasets.  Select this link for more details nrungcm

namip – Controls source of Sea Surface Temperatures and Sea-ice.  Select this link for more details namip

rescrn – Recomputes near-surface diagnostics for consistency in output (rescrn=1)

maxtilesize – Controls vector length for physics routines.  Can lead to speed improvements when optimized for the host computer.

Dynamical core

precon – Controls the method used to solve the Helmholtz equation (precon=-10000 for multi-grid, precon=0 for conjugate-gradient and precon=-3900 is for SOR).

restol – Tolerance of the iterative solution for the Helmholtz equation

nh – Allows for hydrostatic (nh=0) and non-hydrostatic (nh=5) dynamics

knh – Delays the use of the non-hydrostatic dynamics for the specified number of time-steps.  Has no effect if the initial conditions are a CCAM restart file.  Effectively knh only works after interpolating initial conditions from a lower resolution.

epsp – Off-centring term for pressure where epsp=-1 is fully explicit, epsp=0 is half explicit and half implicit, whereas epsp=1 is fully implicit

epsu – Off-centring term for momentum where epsu=-1 is fully explicit, epsu=0 is half explicit and half implicit, whereas epsu=1 is fully implicit

epsh – Off-centring term for non-hydrostatic equation where epsh=-1 is fully explicit, epsh=0 is half explicit and half implicit, whereas epsh=1 is fully implicit

nstagu – Controls period of switching direction for reversible staggering

khor – Controls strength of horizontal diffusion at different vertical levels

nhorjlm – Method used for horizontal diffusion (nhorjlm=0 for Smagorinsky, nhorjlm=1 for deformation, nhorjlm=3 for Smag+TKE)

nhorps – Controls horizontal diffusion for which terms (nhorps=0 for all, nhorps=-1 for T&Q, nhorps=-2 for U&V, nhorps=-3 for Q, nhorps=-4 for T,Q,cloud&aerosols)

always_mspeca – Forces CCAM to recalculate dynamics and radiation variables on the first time-step instead of using data from the restart file.

Mass fixer

mfix – Turns mass fixer on (mfix=1) or off (mfix=0) to conserve surface pressure.

mfix_qg – Turns moisture fixer on (mfix_qg=1) or off (mfix_qg=0) to conserve moisture fields (i.e., qv, ql, qf, qs, qg)

mfix_aero – Turns aerosol mass fixed on (mfix_aero=0) or off (mfix_aero=0) to conserve aerosol fields

qg_fix – Correction for saturated air.  Options are disabled (qg_fix<=-1), internal checks (qg_fix>=0), remove negative moisture (qg_fix>=1) remove saturated moisture (qg_fix>=2)

Nudging

nbd – Far-field nudging options (nbd=-3).  Spectral filter (mbd) is now the preferred option.

mbd – Spectral filter.  mbd=20 is the nudging for the length of the front panel.  mbd=40 is half the size of the front panel, etc.  Possibly overwritten by mbd_maxscale or mbd_maxgrid.

mbd_maxscale – Overrides mbd to limit the maximum length in kilometres.  Default value set to 3000 km.

mbd_maxgrid – Overrides mbd to limit the maximum length in grid points, instead of width of the front panel.

mbd_maxscale_mlo – Same as mbd_maxscale, but applied to the ocean model.

mbd_maxgrid_mlo – Same as mbd_maxgrid, but applied to the ocean model.

mloalpha – Nudging strength for the ocean model. mloalpha=10 is full strength, mloalpha=20 is half strength, etc.

nud_p – Turn on (nud_p=1) or off (nud_p=0) nudging for surface pressure.

nud_t – Turn on (nud_t=1) or off (nud_t=0) nudging for air temperture.

nud_q – Turn on (nud_q=1) or off (nud_q=0) nudging for water vapor.

nud_uv – Turn on (nud_uv=1) or off (nud_uv=0) nudging for winds.

nud_aero – Turn on (nud_aero=1) or off (nud_aero=0) nudging for aerosols.

nud_sst – Turn on (nud_sst=1) or off (nud_sst=0) nudging for ocean potential temperature.

nud_sss – Turn on (nud_sss=1) or off (nud_sss=0) nudging for ocean salinity.

nud_ouv – Turn on (nud_ouv=1) or off (nud_ouv=0) nudging for ocean currents.

nud_sfh – Turn on (nud_sfh=1) or off (nud_sfh=0) nudging for ocean surface height.

nud_hrs – E-folding time for far-field nudging.

nud_period – Limits the period (in mins) to nudge the atmosphere or ocean with the scale-selective filter.  Actual nudging period is the minimum of nud_period and the period of data in the host model.

kbotdav – Lowest level for atmosphere nudging.  -ve value specifies a pressure level with -1000 for 1000 hPa, etc

ktopdav – Highest level for atmosphere nudging.  -ve value specifies a pressure level with -1 for 1 hPa, etc

ktopmlo – Highest level for ocean nudging.  -ve value specifies a depth in sigma values with -1 being 0.001 sigma level

kbotmlo – Lowest level for ocean nudging.  -ve value specifies a depth in sigma values with -1000 being 1 sigma level

sigramplow – Linear ramp rate to grow atmospheric nudging in sigma levels from kbotdav

sigramphigh – Linear ramp rate to grow atmospheric nudging in sigma levels from ktopdav

Ensemble

ensemble_mode – Mode for CCAM ensemble with 0=off, 1=control and 2=breeding

ensemble_period – Update period for ensemble members (mins).  Default value is 720 mins

ensemble_rsfactor – Scale factor for ensemble perturbation.  1.=no-scaling.  Default value is 0.1

Oceans, lakes and rivers

nmlo – Options for ocean model.  nmlo=0 for off, nmlo=-1 for single column ocean and nmlo=-3 for dynamical ocean

ol – Number of vertical levels for the ocean model

tss_sh – Sea Surface Temperature skin temperature enhancement factor

nriver – Turns on (nriver=-1) or off (nriver=0) the river routing model

Land, urban and carbon

nsib – Selects the land-surface model with nsib=3 for original, nsib=5 for MODIS and nsib=7 for CABLE

nurban – Turns on (nurban=-1) or off (nurban=0) the urban canopy model (aTEB)

vmodmin – Minimum wind speed for calculating surface fluxes in m/s

nsigmf – Modifies soil behaviour with nsib=3 or nsib=5 to essentially increase the heat capacity.  Not recommended for nrad=5

jalbfix – Modifies albedo with nsib=3 or nsib=5 to increase the albedo over sandy soils.  Not recommended for nrad=5

Radiation and aerosols

nrad – Radiation model with nrad=4 for original and nrad=5 for SEA-ESF (from GFDL AM3)

iaero – Specifies aerosol model.  See the following link for further details iaero

Boundary layer turbulent mixing

nvmix – Boundary layer turbulence model with nvmix=3/7 for local-Ri and nvmix=6 for EDMF with k-e closure

nlocal – Counter gradient model with nlocal=0 for off, nlocal=6 for diagnosed and nlocal=7 (with nvmix=6) for mass-flux

Station output

nstn – Number of output stations

slon – List of longitudes for station output

slat – List of latitudes for station output

File input/output

localhist – Allows CCAM to write output in parallel.  localhist=.true. can lead to significant speed improvements for higher numbers of CPUs.

unlimitedhist – Use unlimited dimension for output file with unlimitedhist=.true.  There can be some speed advantages for using unlimitedhist=.false. although visualizing the data can be difficult.

synchist – Flush output buffers after writing data with synchist=.true.  synchist=.true. can be useful for debugging.

compression – Compression level for output from 0 (no compression) to 9 (high compression).  compression=1 is recommended.

hp_output – Output file precision (0=short, 1=float).  Using hp_output=0 for short precision can halve the file size.