== [=#virtual_measurement_input '''Virtual measurement input file'''] ==

The virtual measurement input file comprises all information required to setup virtual sites within the model domain. Therefore, different global attributes as well as variables are mandatory. Please note, each attribute and variable name is in the format ''name<id>'', where id is an integer number running from 1 to [#num_vm number of stations].  
The following global attributes must be present in the virtual setup file.

||='''Global attributes'''  =||='''Type''' =||='''Explanation / Remarks'''  =||
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#num_vm '''number_of_stations''']
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_INT
}}}
{{{#!td
Number of considered sites. 
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#origin_x2 '''origin_x<id>''']
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_FLOAT
}}}
{{{#!td
Origin ''x''-coordinate of the measurement site in UTM.
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#origin_y2 '''origin_y<id>''']
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_FLOAT
}}}
{{{#!td
Origin ''y''-coordinate of the measurement site in UTM.
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#site '''site<id>''']
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_CHAR
}}}
{{{#!td
Name of the site. The name of the site will be used to name the final NetcDF files. 
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#featuretype '''featureType<id>''']
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_CHAR
}}}
{{{#!td
Type of the measurement. Allowed strings are: ''timeSeries'', ''timeSeriesProfile'', and ''trajectory''. 
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#soilsample '''soil_sample<id>''']
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_BYTE
}}}
{{{#!td
Bit value indicating that at the current site also soil quantities should be sampled ( = 1 ). If no soil quantities are sampled this value should be 0.  
}}}

\\\\
In the following, the required dimensions/variables will be listed. Please note, NetCDF dimensions of the coordinate variables ''E_UTM'', ''N_UTM'', ''z'', and ''station_h'' depend on the [#featuretype type] of the measurement. For ''timeseries'', the observation is a stationary one with a fixed number of locations. The number of fixed coordinates (e.g. several sensors at a mast, i.e. for each site there can be several stations) is stored in the dimension station<id>. For ''timeSeriesProfile'' or ''trajectory'', however, the coordinate variables depend on the dimensions ''tray<id>'' and ''ntime<id>'', being the number of trajectories and the maximum number of timesteps measured for a trajectory, according to the '''[UC]2 data standard'''.

||='''Variables'''  =||='''Type''' =||='''Explanation / Remarks'''  =||
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#eutm '''E_UTM<id>''' (station<id>) or (tray<id>,ntime<id>)]
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_FLOAT
}}}
{{{#!td
UTM easting coordinate of the measurement location(s). 
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#nutm '''N_UTM<id>''' (station<id>) or (tray<id>,ntime<id>)]
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_FLOAT
}}}
{{{#!td
UTM northing coordinate of the measurement location(s). 
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#zag '''z<id>''' (station<id>) or (tray<id>,ntime<id>)]
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_FLOAT
}}}
{{{#!td
Sensor height above sea level. The relative measurement height calculates from {{{z-station_h}}}. 
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#station_h '''station_h<id>''' (station<id>) or (tray<id>,ntime<id>)]
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_FLOAT
}}}
{{{#!td
Surface altitude with respect to sea level.
}}}
|----------------
{{{#!td style="vertical-align:top;width: 150px"
[=#measured_variables '''measured_variables<id>'''(num_vars<id>,10)]
}}}
{{{#!td style="vertical-align:top;width: 50px"
NC_CHAR
}}}
{{{#!td
List of character strings (length = 10) with variable names. 
}}}

\\\\

=== [=#example '''Creating input setup files'''] ===

An example setup file for virtual measurements can be found [[attachment:vm_driver|here]]. This file was created with the script [source:palm/trunk/SCRIPTS/palm_cvd palm_cvd] which comes with revision -r4400. To execute the script just run {{{palm_cvd .cvd.config_<your file suffix>}}}. [source:palm/trunk/SCRIPTS/palm_cvd palm_cvd] can be steered with a configuration file. In case 'real-world' campaigns shall be emulated, [source:palm/trunk/SCRIPTS/palm_cvd palm_cvd] reads the relevant coordinate information of the observational data, the sampled quantities as well as further metatdata, and merges these into a setup file, so that PALM can internally setup the corresponding sampling locations on the numeric grid. Therefore,  [source:palm/trunk/SCRIPTS/palm_cvd palm_cvd] assumes that the 'real-world' data follows the (UC)2 data standard. With this approach, trajectory measurements (e.g. airborne- or other mobile measurements), stationary tower measurements, or vertical soundings can be emulated in PALM. \\
Further, independent of any campaign data, it is possible to prescribe additional sites with [source:palm/trunk/SCRIPTS/palm_cvd palm_cvd],  where the respective UTM coordinates and the sampled quantities need to be specified in the config file. At the moment only stationary coordinates can be specified in the config file. However, it is planned to extend palm_cvd and its config file to be able to specify also trajectory measurements or more advanced sampling approaches such as Lidar scans.