== Runtime parameters ==
==== [#output Output steering] ====
==== [#run Run steering] ====
\\\\
[=#output '''Output steering:]\\
||='''Parameter Name'''  =||='''FORTRAN Type'''  =||='''Default Value'''  =||='''Explanation'''  =||
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#averaging_interval '''averaging_interval''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
R
}}}
{{{#!td style="vertical-align:top; width: 100px"
0.0
}}}
{{{#!td
Averaging interval for all output of temporally averaged data (in s).\\\\
This parameter defines the time interval length for temporally averaged data (vertical profiles, spectra, 2d cross-sections, 3d volume data). By default, data are not subject to temporal averaging. The interval length is limited by the parameter
[#dt_data_output_av dt_data_output_av]. In any case, '''averaging_interval <= dt_data_output_av''' must hold.\\\\
If an interval is defined, then by default the average is calculated from the data values of all timesteps lying within this interval. The number of time levels entering into the average can be reduced with the parameter [[dt_averaging_input]].\\\\
If an averaging interval can not be completed at the end of a run, it will be finished at the beginning of the next restart run. Thus for restart runs, averaging intervals do not necessarily begin at the beginning of the run.\\\\
Parameters [#averaging_interval_pr averaging_interval_pr] and [[averaging_interval_sp]] can be used to define different averaging intervals for vertical profile data and spectra, respectively.
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#averaging_interval_pr '''averaging_interval_pr''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
value of [#averaging_interval averaging_interval]
}}}
{{{#!td
Averaging interval for output of vertical profiles to local file [[DATA_1D_PR_NETCDF]] (in s).\\\\
If this parameter is given a non-zero value, temporally averaged vertical profile data are output. By default, profile data data are not subject to temporal averaging. The interval length is limited by the parameter [[dt_dopr]]. In any case '''averaging_interval_pr <= dt_dopr''' must hold.\\\\
If an interval is defined, then by default the average is calculated from the data values of all timesteps lying within this interval. The number of time levels entering into the average can be reduced with the parameter [[dt_averaging_input_pr]].\\\\
If an averaging interval can not be completed at the end of a run, it will be finished at the beginning of the next restart run. Thus for restart runs, averaging intervals do not necessarily begin at the beginning of the run.
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#data_output '''data_output''']
}}}
{{{#!td style="vertical-align:top"
C * 10 (100)
}}}
{{{#!td style="vertical-align:top"
100 * ' '
}}}
{{{#!td
Quantities for which 2d cross section and/or 3d volume data are to be output.\\\\
PALM allows the output of instantaneous data as well as of temporally averaged data which is steered by the strings assigned to this parameter (see below).\\\\
By default, cross section data are output (depending on the selected cross sections(s), see below)  to local files [[DATA_2D_XY_NETCDF]], [[DATA_2D_XZ_NETCDF]] and/or [[DATA_2D_YZ_NETCDF]]. Volume data are output to file [[DATA_3D_NETCDF]]. If the user has switched on the output of temporally averaged data, these are written seperately to local files [[DATA_2D_XY_AV_NETCDF]], [[DATA_2D_XZ_AV_NETCDF]], [[DATA_2D_YZ_AV_NETCDF]], and [[DATA_3D_AV_NETCDF]], respectively.\\\\
The filenames already suggest that all files have netCDF format. Informations about the file content (kind of quantities, array dimensions and grid coordinates) are part of the self describing netCDF format and can be extracted from the netCDF files using the command "ncdump -c <filename>". See ''[[../iofiles|netCDF data]]'' about processing the PALM netCDF data.\\\\
The following quantities are available for output by default (quantity names ending with '*' are only allowed for the output of horizontal cross sections
<insert explanation>
||='''quantity name''' =||='''meaning''' =||='''unit''' =||='''remarks''' =||
||e  ||SGS || m^2^/s^2^ ||
||lwp* ||liquid water path ||m ||only horizontal cross section is allowed, [[requires cloud_physics]] = ''.T.'' ||
<insert explanation>

}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dt_data_output_av '''dt_data_output_av''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
0.0
}}}
{{{#!td

}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
\\\\
'''Run steering:[=#run] '''\\
||='''Parameter Name'''  =||='''FORTRAN Type'''  =||='''Default Value'''  =||='''Explanation'''  =||
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#call_psolver_at_all_substeps '''call_psolver_at_all_substeps''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
L
}}}
{{{#!td style="vertical-align:top; width: 100px"
.T.
}}}
{{{#!td
Switch to steer the call of the pressure solver.\\\\
In order to speed-up performance, the Poisson equation for perturbation pressure (see [[psolver]]) can be called only at the last substep of multistep Runge-Kutta timestep schemes (see [[timestep_scheme]]) by setting '''call_psolver_at_all_substeps''' = ''.F.''. In many cases, this sufficiently reduces the divergence of the velocity field. Nevertheless, small-scale ripples (2-delta-x) may occur. In this case and in case of non-cyclic lateral boundary conditions, '''call_psolver_at_all_timesteps''' = ''.T.'' should be used. 
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#cfl_factor '''cfl_factor''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
0.1, 0.8 or 0.9 (see right)
}}}
{{{#!td
Time step limiting factor.\\\\
In the model, the maximum allowed time step according to CFL and diffusion-criterion dt_max is reduced by [[dt]] = dt_max * '''cfl_factor''' in order to avoid stability problems which may arise in the vicinity of the maximum allowed timestep. The condition 0.0 < '''cfl_factor''' < 1.0 applies.\\\\
The default value of cfl_factor depends on the [[timestep_scheme]] used:\\\\
For the third order Runge-Kutta scheme it is '''cfl_factor''' = 0.9.\\\\
In case of the leapfrog scheme a quite restrictive value of '''cfl_factor''' = 0.1 is used because for larger values the velocity divergence significantly effects the accuracy of the model results. Possibly larger values may be used with the leapfrog scheme but these are to be determined by appropriate test runs.\\\\
The default value for the Euler scheme is '''cfl_factor''' = 0.8 .
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#create_disturbances '''create_disturbances''']
}}}
{{{#!td style="vertical-align:top"
L
}}}
{{{#!td style="vertical-align:top"
.T.
}}}
{{{#!td
Switch to impose random perturbations to the horizontal velocity field.\\\\
With '''create_disturbances''' = .T., random perturbations can be imposed to the horizontal velocity field at certain times e.g. in order to trigger off the onset of convection, etc..\\\\
The temporal interval between these times can be steered with [[dt_disturb]], the vertical range of the perturbations with [[disturbance_level_b]] and [[disturbance_level_t]], and the perturbation amplitude with [[disturbance_amplitude]]. In case of non-cyclic lateral boundary conditions (see [[bc_lr]] and [[bc_ns]]), the horizontal range of the perturbations is determined by [[inflow_disturbance_begin]] and [[inflow_disturbance_end]]. A perturbation is added to each grid point with its individual value determined by multiplying the disturbance amplitude with a uniformly distributed random number. After this, the arrays of u and v are smoothed by applying a Shuman-filter twice and made divergence-free by applying the pressure solver.\\\\
The random number generator to be used can be chosen with [[random_generator]].\\\\
As soon as the desired flow features have developed (e.g.  convection has started), further imposing of perturbations is not necessary and can be omitted (this does not hold for non-cyclic lateral boundaries!). This can be steered by assigning an upper limit value for the perturbation energy (the perturbation energy is defined by the deviation of the velocity from the mean flow) using the parameter [[disturbance_energy_limit]]. As soon as the perturbation energy has exceeded this energy limit, no more random perturbations are assigned.\\\\
Timesteps where a random perturbation has been imposed are marked in the local file [[RUN_CONTROL]] by the character "D" appended to the values of the maximum horizontal velocities. 
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#cycle_mg '''cycle_mg''']
}}}
{{{#!td style="vertical-align:top"
C*1
}}}
{{{#!td style="vertical-align:top"
'w'
}}}
{{{#!td
Type of cycle to be used with the multi-grid method.\\\\
This parameter determines which type of cycle is applied in the multi-grid method used for solving the Poisson equation for perturbation pressure (see [[psolver]]). It defines in which way it is switched between the fine and coarse grids. So-called v- and w-cycles are realized (i.e. '''cycle_mg''' may be assigned the values 'v' or 'w'). The computational cost of w-cycles is much higher than that of v-cycles, however, w-cycles give a much better convergence. 
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dummy '''dummy''']
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td style="vertical-align:top"
dummy
}}}
{{{#!td
dummy
}}}