== [=#salsa_input '''Aerosol input file'''] ==

The aerosol (salsa) driver contains surface-emission information of aerosol particles for the aerosol module SALSA. Aerosol emissions can be given using two levels of detail (lod):
 * lod=1: given as total mass emissions per emission category without information on the size distribution
 * lod=2: given as total aerosol number containing information also on the aerosol size distribution

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=== [=#attr '''Global attributes'''] === 

No mandatory attributes. For good documentation, please consider applying global attributes listed for the [../static static driver].

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=== [=#attrlist '''List of attributes'''] ===
The following list gives an overview of attributes that can be assigned to variables in an aerosol driver file.
||='''Attribute'''  =||= '''Type'''  =||= '''Value''' =||= '''Description''' =||
||{{{_FillValue}}}   || Variable-specific || Variable-specific       || Fill value for missing data ||
||{{{lod}}}          || NC_INT   || Variable-specific                || Level of detail used for some variables ||
||{{{long_name}}}    || NC_CHAR  || Variable-specific                || Variable long name ||
||{{{source}}}       || NC_CHAR  || Variable-specific                || Data source ||
||{{{units}}}        || NC_CHAR  || Variable-specific                || Units of the variable ||

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=== [=#dimensions '''List of dimensions'''] ===
The following list provides an overview of all dimension variables that can be used in an aerosol driver file. 
||='''Dimension'''  =||= '''Type'''  =||= '''Value''' =||= '''Description''' =||
||''composition_index'' || NC_INT || - || Index of each chemical component in [#composition_name ''composition_name''] and [#emission_mass_fracs ''emission_mass_fracs''] ||
||''max_string_length'' || NC_INT || 25 || Maximum string length in [#composition_name ''composition_name''] and [#emission_category_name ''emission_category_name''] ||
||''ncat'' || NC_INT || - || number of elements in [#pavement_pars ''pavement_pars''] ||
||''npavement_subsurface_pars'' || NC_INT || 2 || Number of emission categories in [#emission_category_name ''emission_category_name''], [#emission_mass_fracs ''emission_mass_fracs''], [#emission_number_fracs ''emission_number_fracs''] and [#aerosol_emission_values ''aerosol_emission_values''] ||
||''nhoursyear'' || NC_INT || 8760/8784 || Number of hours per year in [#emission_time_factors ''emission_time_factors''] (sum must equal to 1). ||
{{{#!td style="vertical-align:top"
[=#composition_name ''nmonthdayhour''] 
}}}
{{{#!td style="vertical-align:top"
NC_INT
}}}
{{{#!td style="vertical-align:top"
91
}}}
{{{#!td style="vertical-align:top"
Number of required input values for emission time rescaling factors in [#emission_time_factors ''emission_time_factors'']:\\
   {{{#!td
         ||= ''Index'' =||= Description  =||
         ||  1-12  ||scaling per month (sum must be 1)                  ||
         ||  13-19 ||scaling per day of week (sum must be 1)            ||
         ||  20-43 ||scaling per hour for a working day (sum must be 1) ||
         ||  44-67 ||scaling per hour for a Saturday (sum must be 1)    ||
         ||  68-91 ||scaling per hour for a Sunday (sum must be 1)      || 

   }}}
}}}

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=== [=#coordinates '''List of coordinate variables'''] ===
The following list provides an overview of all coordinate variables that can be used in an aerosol driver file.
||='''Variable'''   =||= '''Type'''  =||='''Attributes''' =||= '''Remarks''' =||
||''Dmid''              || NC_FLOAT ||{{{long_name="geometric mean diameter of an aerosol size bin}}}\\{{{units="m"}}} || Geometric mean diameter of a aerosol size bin (in m). Has to conform the size bin description given using [wiki:doc/app/salsa_parameters#nbin nbin] and [wiki:doc/app/salsa_parameters#nbin reglim] in salsa_parameters. ||
||''time''              || NC_FLOAT ||{{{long_name="time}}}\\{{{units="seconds since YYYYMMDD hh:mm UTC"}}} || Time in seconds since the beginning of the simulation (in UTC time). E.g., 7am (UTC+3) = 14400 ||
||''x''              || NC_FLOAT ||{{{axis="X"}}}\\{{{long_name="distance to origin in x-direction}}}\\{{{units="m"}}} || ||
||''y''              || NC_FLOAT ||{{{axis="Y"}}}\\{{{long_name="distance to origin in y-direction}}}\\{{{units="m"}}} || ||

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=== [=#emission_cat '''Emission categories'''] ===
The following list provides an overview of all variables to describe the emission categories in an aerosol driver file.

||='''Input variable'''  =||='''Type'''  =||='''Attributes''' =||='''Remarks'''  =||
||[=#emission_category_index ''emission_category_index(ncat)'']   || NC_BYTE       ||{{{long_name="emission category index"}}}  || Index of the emission category(ies) given in [#emission_category_name ''emission_category_name'']. ||
||[=#emission_category_name ''emission_category_name(ncat,max_string_length)''] || NC_CHAR     ||{{{long_name="emission category name"}}} || Currently available categories:
"traffic exhaust",
"road dust" and
"wood combustion".
Applied to construct size distributions for aerosol emissions if {{{aerosol_emission_values:lod=1}}}, i.e., the size distributions are not specifically given using [#emission_numbers_fracs ''emission_number_fracs'']. || 

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=== [=#emission_number_mass_fracs '''Number size distribution and mass composition of aerosol emission per category'''] ===
The following list provides an overview of all variables to describe the number size distribution and mass composition of aerosol emissions in an aerosol driver file.

||='''Input variable'''  =||='''Type'''  =||='''Attributes''' =||='''Remarks'''  =||
{{{#!td style="vertical-align:top"
[=#composition_name ''composition_name(composition_index,max_string_length)''] 
}}}
{{{#!td style="vertical-align:top"
NC_CHAR
}}}
{{{#!td style="vertical-align:top"
{{{long_name="aerosol composition name"}}}
}}}
{{{#!td style="vertical-align:top"
Name of different chemical components in [#emission_mass_fracs ''emission_mass_fracs'']. List of the available chemical components:\\
   {{{#!td
         ||= ''Component'' =||= Description  =||
         ||  'H2SO4', 'SO4', 'h2so4', 'so4'          ||Sulphur / sulphuric acid ||
         ||  'OC', 'oc'                              ||Organic carbon           ||
         ||  'BC', 'bc'                              ||Black carbon             ||
         ||  'DU', 'du'                              ||Dust                     ||
         ||  'SS', 'ss'                              ||Sea salt                 || 
         ||  'HNO3', 'NO3', 'NO', 'hno3', 'no3', 'no'||Nitrares / nitric acid   ||
         ||  'NH3', 'NH4', 'NH', 'nh3', 'nh4', 'nh'  ||Ammonium / ammonia       ||

   }}}
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#emission_mass_fracs ''emission_mass_fracs(ncat,composition_index)''] 
}}}
{{{#!td style="vertical-align:top"
NC_FLOAT
}}}
{{{#!td style="vertical-align:top"
{{{_FillValue=-9999.f}}}\\{{{long_name="mass fractions of chemical components in aerosol emissions"}}}
}}}
{{{#!td style="vertical-align:top"
Mass fraction of different chemical components listed in [#composition_name ''composition_name''].
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#emission_number_fracs ''emission_number_fracs(ncat,Dmid)''] 
}}}
{{{#!td style="vertical-align:top"
NC_FLOAT
}}}
{{{#!td style="vertical-align:top"
{{{_FillValue=-9999.f}}}\\{{{long_name="number fractions of aerosol size bins in aerosol emissions"}}}
}}}
{{{#!td style="vertical-align:top"
Number fraction of each aerosol size bin. Bin mean diameters are given in [#Dmid ''Dmid'']. Only applied when {{{aerosol_emission_values:lod=2}}}.
}}}

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=== [=#temporal_scaling '''Temporal scaling variables'''] ===
The following list provides an overview of all variables used to scale [#aerosol_emission_values ''aerosol_emission_values''] if {{{aerosol_emission_values:lod=1}}}.

||='''Input variable'''  =||='''Type'''  =||='''Attributes''' =||='''Remarks'''  =||
{{{#!td style="vertical-align:top"
[=#emission_time_factors ''emission_time_factors(ncat,[nmonthday],[nhoursyear])''] 
}}}
{{{#!td style="vertical-align:top"
NC_FLOAT
}}}
{{{#!td style="vertical-align:top"
{{{lod=1/2}}}\\{{{long_name="emission time scaling factors"}}}
}}}
{{{#!td style="vertical-align:top"
Emission time scaling factors for aerosol_emission_values. Two levels of detail (lod) are possible:\\
 * lod=1: scaling according to month-day-hour classification (see nmonthdayhour)
 * lod=2: scaling for each hour of the year (see nhoursyear)
}}}

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=== [=#emission_values '''Surface emission data'''] ===
In order to enable surface emissions of aerosol particles, one must set [wiki:doc/app/salsa_parameters#salsa_emission_mode salsa_emission_mode]  = 'read_from_file' in salsa_parameters.

||='''Input variable'''  =||='''Type'''  =||='''Attributes''' =||='''Remarks'''  =||
{{{#!td style="vertical-align:top"
[=#aerosol_emission_values ''aerosol_emission_values([time],y,x,ncat)''] 
}}}
{{{#!td style="vertical-align:top"
NC_FLOAT
}}}
{{{#!td style="vertical-align:top"
{{{_FillValue=-9999.f}}}\\{{{lod=1/2}}}\\{{{long_name="aerosol emission values"}}}\\{{{units='#/m2/s'}}}
}}}
{{{#!td style="vertical-align:top"
Emission values of aerosol particles. The coordinates vary based on the chosen level of detail.\\
 * {{{lod=1}}}: Emissions are provided per emission category and yearly as total PM in dimensions {{{aerosol_emission_values(y,x,ncat)}}}. They are then scaled by pre-defined rescaling factors [#emission_time_factors ''emission_time_factors'']. Default categories are traffic exhaust, road dust, wood combustion, other. 
 * {{{lod=2}}}: Emissions are provided per emission category at given points in time and space in dimensions {{{aerosol_emission_values(time,y,x,ncat)}}} and in units # m^-2^ s^-1^. Total number emissions are then scaled to size bins by [#emission_number_fracs ''emission_number_fracs'']. 
}}}


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=== [=#example '''Example static driver file] ===
{{{
#!div style="align:'left'; width: 400px; border: 0px solid; float:right"

}}} 
An example aerosol driver file can be downloaded [https://palm.muk.uni-hannover.de/trac/browser/palm/trunk/TESTS/cases/urban_environment_salsa here]. Furthermore, example scripts for creating a salsa driver (and also a salsa dynamic driver including background concentrations) is attached in the end of this page.