4a. Input to mcarats executable (a): Structure of the namelist input file...

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The executable for radiative transfer simulation is named as "mcarats". A single run of mcarats executable is called here an experiment. For one experiment, four input files can be used:

The namelist input file controls general configurations of the experiment. Other data files are optional, and used for large array data such as scattering phase functions and surface and 3-D atmospheric properties.

Structure of the namelist input file

The namelist file should contain one initialization part and job specification parts for multiple jobs:

nitialization part

Job specification part for job 1

Job specification part for job 2

Job specification part for job 3

...

The following subsections describe details of each input parameters for the namelists and the external files. There are many input parameters. In addition, this document could not be complete. To learn how to set up the parameters for the user's purpose, the easiest way might be to explore the example cases, for which input data files are included in the package.

Cases are provided for 3-D inhomogeneous, overcast stratocumulus cloud over homogeneous surface

  • Remote sensing ("rs") experiment: calculation of pixel-averaged, reflected radiances at the top of atmosphere (TOA)

  • Camera image ("ci") experiment: calculation of local angle-averaged radiances looking the 3-D scene

  • Heating rate ("hr") experiment: calculation of 3-D distributions of pixel-averaged fluxes and volume-averaged heating rates

Full list of input variables

namelist /mcarWld_nml_init/Wld_mverb, Wld_jseed, Wld_mbswap, Wld_mtarget, Wld_moptim, Wld_njob

namelist /mcarSca_nml_init/Sca_inpfile, Sca_mfmt, Sca_npf, Sca_nangi, Sca_nanci, &

& Sca_ipsta, Sca_ipwid, Sca_nchi, Sca_qtfmax, Sca_ntg

namelist /mcarAtm_nml_init/Atm_inpfile, Atm_mfmt, Atm_iz3l, Atm_nx, Atm_ny, Atm_nz, &

& Atm_nz3, Atm_nkd, Atm_np1d, Atm_np3d, Atm_mtprof, Atm_nqlay

namelist /mcarSfc_nml_init/Sfc_inpfile, Sfc_mfmt, Sfc_mbrdf, Sfc_nxb, Sfc_nyb, Sfc_nsco, Sfc_nsuz

namelist /mcarSrc_nml_init/Src_nsrc

namelist /mcarFlx_nml_init/Flx_mflx, Flx_mhrt, Flx_diff0, Flx_diff1

namelist /mcarRad_nml_init/Rad_mrkind, Rad_mpmap, Rad_mplen, Rad_nrad, Rad_nxr, &

& Rad_nyr, Rad_nwf, Rad_ntp, Rad_tpmin, Rad_tpmax

namelist /mcarVis_nml_init/Vis_mrend, Vis_epserr, Vis_fpsmth, Vis_nqhem, Vis_nqlay, Vis_fatten

namelist /mcarPho_nml_init/Pho_iso_SS, Pho_iso_tru, Pho_iso_max, Pho_wsml, Pho_wmin, Pho_wmax, &

& Pho_wfac, Pho_pfpeak

namelist /mcarWld_nml_job/Wld_rmlcf, Wld_nplcf, Wld_dtaumin

namelist /mcarAtm_nml_job/Atm_idread, Atm_dx, Atm_dy, Atm_zgrd0, Atm_tmp1d, Atm_ext1d, Atm_omg1d, &

& Atm_apf1d, Atm_wkd0, Atm_abs1d, Atm_fext1d, Atm_fext3d, Atm_fabs1d, Atm_fabs3d, &

& Atm_taumin, Atm_fsupg, Atm_fsupi, Atm_nzzsup

namelist /mcarSfc_nml_job/Sfc_idread, Sfc_tmp, Sfc_mtype, Sfc_param, Sfc_nqpot, Sfc_rrmax, &

& Sfc_rrexp, Sfc_nudsm, Sfc_nurpv, Sfc_nulsrt

namelist /mcarSrc_nml_job/Src_wlen, Src_dwlen, Src_flx, Src_qmax, Src_the, Src_phi, Src_xpos, &

& Src_ypos, Src_zloc, Src_apsize, Src_mtype, Src_mphi

namelist /mcarRad_nml_job/Rad_mrproj, Rad_difr0, Rad_difr1, Rad_zetamin, Rad_frmod, Rad_xpos, &

& Rad_ypos, Rad_wfunc0, Rad_zloc, Rad_rmin0, Rad_rmax0, Rad_the, Rad_phi, Rad_psi, Rad_umax, &

& Rad_vmax, Rad_qmax, Rad_apsize

In the followings, variable names, types and shapes of variables, default values, and explanations are described.

Notes on namelist input

The namelist I/O is a feature of Fortran 90. The namelists for mcarats input include many parameters, but the the user does not need to specify all variables' values. This makes the Fortran's namelist flexible and easy to use. For example, when the user gives no value for every variables, then default initialization data will be used. Thus, content of the input file could be as the followings:

&mcarWld_nml_init /

&mcarSca_nml_init /

&mcarAtm_nml_init /

&mcarSfc_nml_init /

&mcarSrc_nml_init /

&mcarFlx_nml_init /

&mcarRad_nml_init /

&mcarVis_nml_init /

&mcarPho_nml_init /

&mcarWld_nml_job /

&mcarAtm_nml_job /

&mcarSfc_nml_job /

&mcarSrc_nml_job /

&mcarRad_nml_job /

Default initialization data are defined in source codes in ./src/mcarats/mcar*.?90, and they are customizable before compiling.

The user can partially set values for one variable in the namelist. For example, a sentence,

Atm_abs1d(1:10,1)=4.0e-5, 3.0e-5, 2.0e-5, 1.0e-5, 5*1.0e-6

sets values for a part of the 2-D array variable Atm_abs1d(iz,ikd), which may be declared as a very large array in the source code.

Another feature of Fortran namelist is a freedom of ordering of each member variable in a namelist block. Any order is acceptable in one namelist block. For details, see Fortran language reference for the compiler.

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