config_site_json

SITE JSON

site.json holds all input data and parameters which could be considers site specific. Besides the key SiteParameters in the top-level JSON object, there might be a few JSON objects which set global/general soil and environment specific parameters. These can either be included from the SQLite database (table user_parameter) or the filesystem or be defined directly in site.json. In order to facilitate easy overwriting of the standard parameters, they are included via the DEFAULT parameter pseudo-key.

The soil profile

The key SoilProfileParameters contains a JSON array of JSON objects which describe the layers of the soil profile. MONICA uses internally 20 layers each with a 10cm thickness. The SoilProfileParameters has to contain at least one layer with a minimal set of soil properties (KA5TextureClass, SoilOrganicCarbon/Matter and SoilRaw/BulkDensity). Additionally to the soil properties a key Thickness which describes the height of the soil layer. The specified soil profile will internally be normalized to 20 10cm layers. If the sizes of the layers won't add up to 2m (MONICAs used profile depth), the last layer will be extend up to 2m. Equally, the layers will be cut at 2m profile depth.

Not all properties are necessary, but the more soil properties are specified, the more exact the calculations will be. If only the KA5TextureClass is given, average values for Sand and Clay content will be used as well as FieldCapacity, PermanentWiltingPoint, PoreVolume and Lambda will be calculated based on them.

Also just one of SoilRawDensity and SoilBulkDensity as well as SoilOrganicCarbon and SoilOrganicMatter have to be given. If both values are being supplied, they should match.

The following table shows the names of the soil properties which can be set on an individual layer.

Name of config file variable	Unit	Description
Thickness	m	thickness of the soil layer
Sand	kg kg-1 (fraction [0-1])	soil sand content, a fraction between 0 and 1
Clay	kg kg-1 (fraction [0-1])	soil clay content, a fraction between 0 and 1
pH		soil pH value
Sceleton	fraction [0-1]	soil stone content, a fraction between 0 and 1
Lambda		soil water conductivity coefficient
FieldCapacity	m3 m-3 (fraction [0-1])	field capacity
PoreVolume	m3 m-3 (fraction [0-1])	saturation
PermanentWiltingPoint	m3 m-3 (fraction [0-1])	permanent wilting point
KA5TextureClass		KA5 soil texture
SoilAmmonium	kg NH4-N m-3	initial soil ammonium content
SoilNitrate	kg NO3-N m-3	initial soil nitrate content
CN		soil C/N ratio
SoilRawDensity	kg m-3	soil raw density
SoilBulkDensity	kg m-3	soil bulk density
SoilOrganicCarbon	% [0-100] ([kg C kg-1] * 100)	soil organic carbon, a percentage between 0 and 100
SoilOrganicMatter	kg OM kg-1 (fraction [0-1])	soil organic matter
SoilMoisturePercentFC	% [0-100]	initial soil moisture in percent of field capacity

Further site specific variables.

Name of config file variable	Unit	Description
Latitude	[decimal degree]	site's latitude
Slope	[height m * length m-1] [0-1]	site's slope
HeightNN	[m]	site's height above sea level
NDeposition		N deposition via atmosphere

Environment parameters for the whole simulation

The following environment parameters for a whole simulation can be adjusted by referencing either the correct json file or overwriting selectively the parameters read from the default file.

Atmospheric CO2 (O3)

Currently the following procedure is being applied.

1. Check if co2 or o3 field is present in daily climate data. If so use the supplied values!
2. If the parameter AtmosphericCO2s (AtmosphericO3s) is set to an JSON object of "year" to "CO2 value" mappings. Then use these yearly values.
3. If the parameter AtmosphericCO2 (AtmosphericCO2) is set to 0 or is negative. Let MONICA calculate the CO2 concentration depending on the year.
4. If none of the points 1.-3. is true, use the value of AtmosphericCO2 (AtmosphericO3) for the whole simulation.

Name of parameter	Unit	Default value	Description
Albedo		0.23
AtmosphericCO2	ppm	0.0
AtmosphericCO2s	ppm	unset	example value: {"1991": 360, "1992": 370, "1993": 380}
AtmosphericO3,	ppm	0.0
AtmosphericO3s	ppm	unset
WindSpeedHeight	m s-1	2.0
LeachingDepth	m	0.0.
MaxGroundwaterDepth	m	18.0
MinGroundwaterDepth	m	20.0
MinGroundwaterDepthMonth	m	3.0

Example site.json file

{
  "SiteParameters": {
    "Latitude": 52.80939865112305,
    "Slope": 0.1,
    "HeightNN": [0 , "m"],
    "NDeposition": 30,
    "SoilProfileParameters": [
      {
        "Thickness": 0.3,
        "SoilOrganicCarbon": [0.8, "%"],
        "KA5TextureClass": "Sl2",
        "SoilRawDensity": ["ld_eff2trd", 2, ["KA5TextureClass2clay", "Sl2"]],
        "Lambda": ["sandAndClay2lambda", ["KA5TextureClass2sand", "Sl2"], ["KA5TextureClass2clay", "Sl2"]]
      },
      {
        "Thickness": 0.1,
        "SoilOrganicCarbon": [0.15, "%"],
        "KA5TextureClass": "Sl2",
        "SoilRawDensity": ["ld_eff2trd", 2, ["KA5TextureClass2clay", "Sl2"]]
      },
      {
        "Thickness": 1.6,
        "SoilOrganicCarbon": [0.05, "%"],
        "KA5TextureClass": "Sl2",
        "SoilRawDensity": ["ld_eff2trd", 2, ["KA5TextureClass2clay", "Sl2"]]
      }
    ]
  },
  "SoilTemperatureParameters": ["include-from-file", "../monica-parameters/user-parameters/hermes-soil-temperature.json"],
  "EnvironmentParameters": {
    "DEFAULT": ["include-from-file", "../monica-parameters/user-parameters/hermes-environment.json"],
    "LeachingDepth": 2.0,
    "WindSpeedHeight": 2.5
  },
  "SoilOrganicParameters": ["include-from-file", "../monica-parameters/user-parameters/hermes-soil-organic.json"],
  "SoilTransportParameters": ["include-from-file", "../monica-parameters/user-parameters/hermes-soil-transport.json"],
  "SoilMoistureParameters": ["include-from-file", "../monica-parameters/user-parameters/hermes-soil-moisture.json"]
}