!!! Currently under construction !!'''

PALM-4U provides a standardized way via the NetCDF data format to input e.g. global attributes, topography data or surface properties, vegetation properties, etc., as well as initialization data and boundary conditions for the prognostic variables.

Input variables are distinguished between static, dynamic, radiation and chemistry variables, while for each type a separate input file exists. The static input file, indicated by the filename supplement _STATIC, contains all static information, such as topography, geographical latitude and longitude, surface property and vegetation information. The dynamic input file, indicated by the filename supplement _STATIC, contains dynamic information on the initial state of the atmosphere or time-dependent boundary conditions. The radiation input file, indicated by _RAD, contains static and dynamic information on radiation properties such as trace gas profiles or sky-view factors. The chemistry input file, indicated by _CHEM, contains static and dynamic information on chemical species and emissions.

The initialization procedure for the surface elements follows a multi-step approach, depending on the given level of detail. In a first step, surfaces elements are initialized horizontally homogeneous with a bulk classification for each type (e.g. vegetation or soil), either set by a default value or set by a namelist-provided value, while the bulk classification provides standard values for a variety of parameters. In a second step, surface elements are initialized individually by providing the bulk classification at each grid point. In case more detailed information is available, all/single parameters can also initialized individually at each grid point.

The provided input data is used to classify each surface element according to its treatment, i.e. default-, natural- or urban-type, in order to treat each surface element accordingly. In case no land-surface or urban-surface scheme is applied, all surfaces are classified as default-type. If a surface element has vegetation, pavement or water, it will be classified as natural-type and is treated by the land-surface scheme, while building surfaces will be treated by the urban-surface scheme.

After reading the input files, PALM-4U performs consistency checks on the provided data. All applied input variables are listed and explained below and additional remarks on restrictions and initialization are given. Please note, this documentation does not comprise all possible global and variables attributes, only those which are required for read by PALM. More detailed information on variable attributes can be found in the PIDS-1.7.

Static input file

Global attributes:

Attribute	Type	Explanation / Remarks
origin_lat	NC_FLOAT	Geographical latitude in degrees north. This attribute defines the south boundary of the model domain and overwrites the namelist parameter latitude, which is used e.g. for the Coriolis parameters as well as for the radiation. Please note, in case of a nested run, values of latitude will be synchronized internally to the respective value of the root parent domain.
origin_lon	NC_FLOAT	Geographical longitude in degrees east. This attribute defines the left boundary of the model domain and overwrites the namelist parameter longitude, which is used e.g. for the radiation. Please note, in case of a nested run, values of longitude will be synchronized internally to the respective value of the root parent domain.
origin_z	NC_FLOAT	Reference height in m above sea level after DHHN2016.

Topography:

In order to prescribe topography from the static input file, topography = 'read_from_file' is required. The minimum requirement for proper topography input is orography_2D.

Input variable	Type	LOD	Explanation / Remarks
orography_2D(y,x)	NC_FLOAT	1 only	Terrain height in m relative to origin_z. If not provided, the relative terrain height will be set to 0 all over the model domain. Please note, orography_2D must not contain any _FillValues.
buildings_2D(y,x)	NC_FLOAT	1	Building height in m relative to the underlying terrain. buildings_2D will be mounted on top of the maximum local terrain height occupied by the respective building. Please note, buildings_2D will not be used if buildings_3D is present on file. If buildings are prescribed, building_id is required.
buildings_3D(z,y,x)	NC_BYTE	2	Building topology relative to the underlying terrain. buildings_3D will be mapped on top of the maximum local terrain height occupied by the respective building. Note, buildings_3D do not need to be prescribed beyond the top level of the highest buildings. If buildings are prescribed, building_id is required.
building_id(y,x)	NC_INT	1 only	Building ID used to identify single building envelopes, which is used for correct mapping of buildings on top of the underlying terrain, as well as for the indoor_model. Please note, building_id must not contain any _FillValue at grid points where buildings_2D/3D is defined.
building_type(y,x)	NC_BYTE	1 only	Building type used to select bulk parameters. building_type is required if the urban-surface model or the indoor_model are applied. Please note, building_type must not contain any _FillValue at grid points where buildings_2D/3D is defined.

Surface variables:

For a proper classification of natural land and water surfaces, pavement_type, soil_type, vegetation_type and water_type are required. Also, the namelist parameter surface_type need to be set to 'netcdf'. Further, if the urban-surface model is applied, also building_type is required. Moreover, at least one of the variables pavement_type, vegetation_type, water_type or building_type need to be defined at each 'xy' location.

Input variable	Type	LOD	Explanation / Remarks
vegetation_type(y,x)	NC_FLOAT	1 only	Bulk classification of non-resolved vegetation surfaces at natural land surface types. At locations where vegetation_type is defined, soil_type must not contain any _FillValues. vegetation_type overwrites the homogeneously prescribed b

Dynamic input file

Radiation input file

Chemistry input file