= Surface output parameters =
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Information about surface properties as well as the actual physical conditions at horizontal and vertical surfaces can be output in NetCDF format (parallel NetCDF4 installation required) or in binary format. The binary output can be further processed and visualized with Paraview via VTK-files which allows the input of unstructured data. 
Output is written into binary files [[../iofiles#SURFACE_DATA_BIN|SURFACE_DATA_BIN]] and  [[../iofiles#SURFACE_DATA_AV_BIN|SURFACE_DATA_AV_BIN]], respectively. 
Please note, in order to visualize surface data with Paraview, the PALM output data needs to be further converted into the VTK file format in the post-processing. A suitable post-processing tool is provided under {{{/trunk/UTIL/surface_output_processing/surface_output_to_vtk.f90}}}. This tool comes with an additional namelist file {{{surface_output_parin}}}, where output specific information such as cycle number, path to the output data, etc. needs to be defined.

To enable model output for unstructured surface data the following namelist is required in your PALM parameter file:    

'''NAMELIST group name:''' [=#surface_data_output_parameters '''{{{surface_data_output_parameters}}}''']
----

||='''Parameter Name'''  =||='''[[../fortrantypes|FORTRAN]]\\[[../fortrantypes|Type]]'''  =||='''Default\\Value'''  =||='''Explanation'''  =||
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#averaging_interval_surf '''averaging_interval_surf''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
R
}}}
{{{#!td style="vertical-align:top; width: 75px"
value of [[../runtime_parameters#averaging_interval|averaging_interval]]
}}}
{{{#!td
Averaging interval for surface output data (in s).
In any case, '''averaging_interval_surf <= dt_dosurf_av''' must hold.
If an interval is defined, then by default the average is calculated from the data values of all time steps lying within this interval. 
}}}
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#data_output_surf '''data_output_surf''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
C * 300 (100)
}}}
{{{#!td style="vertical-align:top; width: 75px"
' '
}}}
{{{#!td
Quantities for which surface data shall be be output. PALM allows the output of instantaneous data as well as of temporally averaged data which is steered by the string '_av' assigned to this parameter (see [[../runtime_parameters#data_output|data_output]] for more explanation). 
For example, '''data_output_surf''' = '' 'shf', 'shf_av', '' will output instantaneous as well as time-averaged data of surface sensible heat flux at all surface elements. 

Surface data for all surfaces elements on the processor subdomain is output in a separate NetCDF file. Further, additional information about polygons and vertices defining the surface elements are output. This information enables to create VTK files with a post-processor (not available yet) which can be read by this visualization software PARAVIEW.  

The following quantities are available for output:
||='''Quantity name''' =||='''Meaning''' =||='''Unit''' =||
||us   ||friction velocity|| m / s ||
||ts   ||scaling parameter for temperature|| K ||
||qs   ||scaling parameter for mixing ratio|| kg / kg ||
||ss   ||scaling parameter for passive scalar|| - ||
||qcs  ||scaling parameter for cloud water mixing ratio || kg / kg ||
||ncs  ||scaling parameter for number concentration of cloud water || 1 / m3 ||
||qrs  ||scaling parameter for rain water mixing ratio || kg / kg ||
||nrs  ||scaling parameter for rain water droplet concentration|| 1 / m3 ||
||ol   ||Obukhov length || m ||
||z0   ||roughness length for momentum || m ||
||z0h  ||roughness length for heat || m ||
||z0q  ||roughness length for moisture || m ||
||theta1  ||potential temperature at 1st grid point outside the wall || K ||
||qv1  ||mixing ratio at 1st grid point outside the wall  || kg / kg ||
||thetav1  || virtual potential temperature at 1st grid point outside the wall || K ||
||usws  ||surface momentum flux for the u-component || m m / ( s s ) ||
||vsws  ||surface momentum flux for the v-component || m m / ( s s ) ||
||shf  ||surface sensible heat flux|| K m / s ||
||qsws ||surface latent heat flux|| kg m / ( kg s ) ||
||ssws ||surface passive scalar flux|| m / s ||
||qcsws ||surface flux of cloud water mixing ratio || m kg / ( s kg ) ||
||ncsws ||surface flux of number concentration of cloud water || 1 / ( s m2 ) ||
||qrsws ||surface flux of rain water mixing ratio || m kg / ( s kg ) ||
||nrsws ||surface flux of rain water droplet concentration|| 1 / ( s m2 ) ||
||sasws || surface salinity flux || - ||
||q_surface || surface moisture || kg / kg ||
||theta_surface || surface temperature || K ||
||thetav_surface || surface virtual temperature || K ||
||rad_net|| radiation balance || W / m2 ||
||rad_lw_in|| total incoming longwave radiation || W / m2 ||
||rad_lw_dif|| incoming longwave radiation flux from sky || W / m2 ||
||rad_lw_out|| outgoing longwave radiation flux || W / m2 ||
||rad_lw_ref|| incoming longwave radiation flux from reflections || W / m2 ||
||rad_lw_res|| residual longwave radiation flux in surfaces after last reflection step || W / m2 ||
||rad_sw_in|| total incoming shortwave radiation flux || W / m2 ||
||rad_sw_dif|| incoming diffused shortwave radiation flux || W / m2 ||
||rad_sw_dir|| direct incoming shortwave radiation flux || W / m2 ||
||rad_sw_out|| outgoing shortwave radiation flux || W / m2 ||
||rad_sw_ref|| incoming shortwave radiation flux from reflections || W / m2 ||
||rad_sw_res|| residual shortwave radiation flux in surfaces after last reflection step || W / m2 ||
||ghf|| ground heat flux  || W / m2 ||
||r_a|| aerodynamic resistance  || 1 / m ||
||r_soil|| soil resistance  || 1 / m ||
||r_canopy|| canopy resistance  || 1 / m ||
||r_s|| total resistance  || 1 / m ||
||uvw1|| surface-parallel flow speed at 1st grid point outside the wall || m / s ||
||waste_heat|| waste_heat, only if [../indoor_parameters indoor_model] is applied || W / m2 ||
||im_hf|| heatflux at innermost building wall, only if [../indoor_parameters indoor_model] is applied || W / m2 ||
||albedo|| aggregated albedo value for the surface based on the tile albedo values || - ||
||emissivity|| aggregated emissivity value for the surface based on the tile emissivity values || - ||
}}}
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#dt_dosurf '''dt_dosurf''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
R
}}}
{{{#!td style="vertical-align:top; width: 75px"
value of [[../runtime_parameters#dt_data_output|dt_data_output]]
}}}
{{{#!td	
Temporal interval at which instantaneous surface data shall be output (in s). Output can be skipped at the beginning of a simulation using parameter [[#skip_time_dosurf|skip_time_dosurf]], which has zero value by default.
}}}
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#dt_dosurf_av '''dt_dosurf_av''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
R
}}}
{{{#!td style="vertical-align:top; width: 75px"
value of [[#dt_dosurf|dt_dosurf]]
}}}
{{{#!td	
Temporal interval at which time averaged surface data shall be output (in s). Output can be skipped at the beginning of a simulation using parameter [[#skip_time_dosurf_av|skip_time_dosurf_av]], which has zero value by default.
}}}
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#skip_time_dosurf '''skip_time_dosurf''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
R
}}}
{{{#!td style="vertical-align:top; width: 75px"
0.0
}}}
{{{#!td	
No surface data output before this interval has passed (in s).
This parameter causes that surface data output activities are starting not before this interval (counting from the beginning of the simulation, t=0) has passed. 
}}}
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#skip_time_dosurf_av '''skip_time_dosurf_av''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
R
}}}
{{{#!td style="vertical-align:top; width: 75px"
0.0
}}}
{{{#!td	
No surfave data output of averaged variables before this interval has passed (in s).
This parameter causes that averaged surface data output activities are starting not before this interval (counting from the beginning of the simulation, t=0) has passed. 
}}}
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#switch_off_module '''switch_off_module''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
L
}}}
{{{#!td style="vertical-align:top; width: 75px"
.F.
}}}
{{{#!td	
 
}}}
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#to_netcdf '''to_netcdf''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
L
}}}
{{{#!td style="vertical-align:top; width: 75px"
.F.
}}}
{{{#!td	
Control parameter enabling surface data output to NetCDF. Note, surface data output to NetCDF is only allowed with [../runtime_parameters/#netcdf_data_format netcdf_data_format] >= 5.
}}}
|----------------
{{{#!td style="vertical-align:top; width: 150px"
[=#to_vtk '''to_vtk''']
}}}
{{{#!td style="vertical-align:top; width: 50px"
L
}}}
{{{#!td style="vertical-align:top; width: 75px"
.F.
}}}
{{{#!td	
Control parameter enabling surface data output to VTK format.
}}}