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Configuring OpenIFS for an aqua-planet simulation requires appropriate changes to:
This controls the configuration for the model's dynamical core.
Edit the fort.4
file (containing the input model namelist) and make sure the settings are as below. You may find this namelist is blank in your file as it does not need altering for normal forecasts, in which case add the following:
&NAMDYNCORE LDYNCORE=true, ! switches on idealized planet configurations. LAQUA=true, ! switches on idealized aqua planet. MSSTSCHEME=1, ! controls SST choice for aquaplanet following Neale & Hoskins (2000a) (see ifs/module/yomdyncore.F90 for more details). ! 1 = Control; 2 = Peaked; 3 = Flat; 4 = Qobs; 5 = Control5N; 6 = 1KEQ, chi=1.0; 7 = 3KEQ, chi=3.0; 8 = 3KW1, chi=3.0 RPLRADI=1, ! Earth radius factor; 1 for normal earth RCORIOI=1, ! Coriolis acceleration factor; 1 for normal Earth NOISEVOR=1, ! if 1 add initial noise in vorticity / |
For more details of the SST configuration, see: ifs/phys_ec/gp_sstaqua.F90
. Modifications to the SST distributions can be made in this routine.
Ensure that the mass conservation correction is enabled to prevent mass drifting in long integrations.
Edit namelist NAMDYN in the fort.4 file and add (or change) this variable:
&NAMDYN LMASCOR=true, ! if true, apply mass correction. / |
Edit namelist NAMCT0 in fort.4 to set the mass correction frequency:
&NAMCT0 NFRMASSCON=24, ! frequency of mass conversation fixups (time-steps) |
Aqua-planet simulations normally use the full model physics and no changes are necessary in the NAEPHY namelist. It is included here for completeness.
If necessary edit the fort.4 file (containing the input model namelist) and make sure the settings are as below.
Note in this example, the model physics is turned on (enabled). By setting LEPHYS=false
, the model would run an aqua-planet with all the physics switched off.
For more information on these switches see the relevant modules in the model code: yoephy.F90
and yoewcou.F90
.
&NAEPHY LEPHYS=true, ! switch the full ECMWF physics package on/off. LEVDIF=true, ! turn on/off the vertical diffusion scheme. LESURF=true, ! turn on/off the interface surface processes. LECOND=true, ! turn on/off the large-scale condensation processes. LECUMF=true, ! turn on/off the mass-flux cumulus convection. LEPCLD=true, ! turn on/off the prognostic cloud scheme. LEEVAP=true, ! turn on/off the evaporation of precipitation LEVGEN=true, ! turn on/off Van Genuchten hydrology (with soil type field) LESSRO=true, ! turn on/off orographic (VIC-type) runoff LECURR=false, ! if true, ocean current boundary condition is used. LEGWDG=true, ! turn on/off gravity wave drag. LEGWWMS=true, ! turn on/off the Warner-McIntyre-Scinocca non-orographic gravity wave drag scheme. LEOZOC=true, ! turn on/off the climatological ozone. LEQNGT=true, ! turn on/off the negative humidity fixer. LERADI=true, ! turn on/off the radiation scheme. LERADS=true, ! turn on/off the interactive surface radiative properties. LESICE=true, ! turn on/off the interactive sea-ice processes. LEO3CH=false, ! turn on/off the ozone chemistry (for prognostic ozone). LEDCLD=true, ! turn on/off the diagnostic cloud scheme. LDUCTDIA=false, ! turn on/off computation and archiving of ducting diagnostics. LWCOU=false, ! turn on/off coupled wave model (n.b. always off for OpenIFS model). LWCOU2W=false, ! turn on/off two-way interaction with the wave model (n.b. always off for OpenIFS model). / |
The above is all that's necessary to enable aqua-planet in the model. However, you may want to experiment with other model options.
&NAMCT0 N3DINI=0, ! normally 0 to initialise the model from a real atmosphere, but see ifs/module/yomdyncore.F90 for other possibilities. |