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SUEWS-SPARTACUS input options

nlayers

Requirement

MD

Type

Integer

Description

Number of vertical layers in the canopy

Configuration

For maximum values, see the used soil code in SUEWS_Soil.txt

use_sw_direct_albedo

Requirement

MD

Type

Boolean

Description

Specify ground and roof albedos separately for direct solar radiation

Configuration

• Only considered when sw_dn_direct_frac>0.

• False (default) - Same ground albedo for diffuse and direct solar radiation Recommended in this version.

• True - Specify ground albedo separately for direct solar radiation

n_vegetation_region_urban

Requirement

MD

Type

Integer

Description

Number of regions used to describe vegetation

Configuration

• 1 (default): heterogeneity of vegetation not considered. might be okay de pending on the level of accuracy needed. See Hogan et al. [2018] – details of SPARTACUS-Vegetation for more information.

• 2: heterogeneity of vegetation considered

n_stream_sw_urban

Requirement

MD

Type

Integer

Description

SW diffuse streams per hemisphere (note: this is the number of quadrature points so a value of 4 corresponds to an ‘8-stream scheme’)

Configuration

4 is recommended. At large computational cost small improvements in accuracy can be made by increasing from 4 [Hogan, 2019].

n_stream_lw_urban

Requirement

MD

Type

Integer

Description

LW streams per hemisphere (note: this is the number of quadrature points so a value of 4 corresponds to an ‘8-stream scheme’)

Configuration

4 is recommended. At large computational cost small improvements in accuracy can be made by increasing from 4 [Hogan, 2019].

sw_dn_direct_frac

Requirement

MD

Type

Float

Description

Fraction of down-welling shortwave radiation that is direct

Configuration

0.45 is based on Berrizbeitia et al. [2020] (Belgium and Berlin annual average), but could be improved.

air_ext_sw

Requirement

MD

Type

Float

Description

Shortwave wavelength-independent air extinction coefficient (m^-1) (i.e. number of radiance e-foldings per metre)

Configuration

0.0 [Hogan, 2019]. Reasonable approximation (personal communication Robin Hogan).

air_ssa_sw

Requirement

MD

Type

Float

Description

Sh ortwave single sca ttering albedo of air

Configuration

• 0.95 [Hogan, 2019]

• air_ext_sw is not used if air_ext_sw=0.0.

veg_ssa_sw

Requirement

MD

Type

Float

Description

Shortwave single scattering albedo of leaves

Configuration

Broadband shortwave vegetation SSA values ranged between 0.41 and 0.52 for RAMI5 Järvselja birch stand forest trees. 0.46 is the default value but users can choose another value if the dominant tree type is one of the RAMI5 Järvselja birch stand forest trees (see Vegetation single scattering albedo (SSA) for details).

air_ext_lw

Requirement

MD

Type

Float

Description

Longwave wavelength-independent air extinction coefficient [m^-1] (i.e. number of radiance e-foldings per metre)

Configuration

0.0 is a bad approximation [Hogan, 2019] but better representation requires several band treatment which is not in SS yet.

air_ssa_lw

Requirement

MD

Type

Float

Description

Longwave single scattering albedo of air

Configuration

• 0.0 is from Hogan [2019].

• air_ssa_lw is not used when air_ext_lw=0.0.

veg_ssa_lw

Requirement

MD

Type

Float

Description

Longwave single scattering albedo of vegetation

Configuration

• 0.06 (Recommended in this version.)

• Should be estimated using a vegetation type in https://speclib.jpl.nasa.gov/library (see Vegetation single scattering albedo (SSA) for details). - Reflectance is ~0.04 for Acer Pensylvanicum, - ~0.02 for Quercus Robur and - ~0.04 for Betula Lenta.

• SSA ~ 2*reflectance so 0.06 is chosen as the default.

veg_fsd

Requirement

MD

Type

Float

Description

Fractional standard deviation of the vegetation extinction. Determines the extinction coefficient in the inner and outer layers of the tree crown when n_vegetation_region_urban=2.

Configuration

• 0.75 (Recommended in this version.)

• Robin has used 0.75 in SS for the RAMI-V radiation-vegetation inter-comparison, but should be updated based on the findings.

veg_contact_fraction

Requirement

MD

Type

Float

Description

Fraction of vegetation edge in contact with building walls

Configuration

• Can be updated from 0.

• If detailed knowledge of the canopy geometry is available.

ground_albedo_dir_mult_fact

Requirement

MD

Type

Float

Description

Ratio of the direct and diffuse albedo of the ground

Configuration

• 1.0 (Recommended in this version.)

• Can be updated from 1: if detailed knowledge of the direct and diffuse albedo is available.

height

Requirement

MU

Type

Float array (dim: nlayers +1)

Description

Height of the layer interfaces [m]

Configuration

to-add

building_frac

Requirement

MU

Type

Float array (dim: nlayers)

Description

Building plan area density

Configuration

Layer 1 building_frac should equal SUEWS Fr_Bldgs

veg_frac

Requirement

MU

Type

Float array (dim: nlayers)

Description

Tree plan area density

Configuration

Layer 1 veg_frac should equal SUEWS Fr_EveTr + Fr_DecTr

building_scale

Requirement

MU

Type

Float array (dim: nlayers)

Description

Building horizontal scale [m]

Configuration

Effective building diameter. Values can be estimated from inspecting buildings using Google Maps or GIS. It is used along with building_frac to calculate the average building perimeter length following Eq. 8 of Spartacus surface documentation.

veg_scale

Requirement

MU

Type

Float array (dim: nlayers)

Description

Vegetation horizontal scale [m]

Configuration

Vegetation scale. Values can be estimated from inspecting vegetation using Google street view. It is used along with veg_fraction to calculate the average vegetation perimeter length following Eq. 2 of Hogan et al. [2018].

roof_albedo

Requirement

MU

Type

Float array (dim: nlayers)

Description

Roof albedo

Configuration

If values are not known then sensible values can be found in SUEWS_NonVeg.txt.

wall_albedo

Requirement

MU

Type

Float array (dim: nlayers)

Description

Roof albedo

Configuration

If values are not known then sensible values can be found in SUEWS_NonVeg.txt.

roof_emissivity

Requirement

MU

Type

Float array (dim: nlayers)

Description

Roof emissivity

Configuration

If values are not known then sensible values can be found in SUEWS_NonVeg.txt.

wall_emissivity

Requirement

MU

Type

Float array (dim: nlayers)

Description

Wall emissivity

Configuration

If values are not known then sensible values can be found in SUEWS_NonVeg.txt.

roof_albedo_dir_mult_fact

Requirement

MD

Type

Float array (dim: nlayers)

Description

Ratio of the direct and diffuse albedo of the roof

Configuration

• 1 is the default value.

• Can be updated from 1. if detailed knowledge of the direct and diffuse albedo is available.

wall_specular_frac

Requirement

MD

Type

Float array (dim: nlayers)

Description

Fraction of wall reflection that is specular

Configuration

• 0 is the default value.

• Can be updated from 0. if the specular reflection is known.