Version 22 (modified by raasch, 14 years ago) (diff)

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Initialization parameters (Namelist @inipar)


Mode:

Parameter Name Type Default Value Explanation

ocean

L

.F.

Parameter to switch on ocean runs.

By default PALM is configured to simulate atmospheric flows. However, starting from version 3.3, ocean = .T. allows simulation of ocean turbulent flows. Setting this switch has several effects:

  • An additional prognostic equation for salinity is solved.
  • Potential temperature in buoyancy and stability-related terms is replaced by potential density.
  • Potential density is calculated from the equation of state for seawater after each timestep, using the algorithm proposed by Jackett et al. (2006, J. Atmos. Oceanic Technol., 23, 1709-1728). So far, only the initial hydrostatic pressure is entered into this equation.
  • z=0 (sea surface) is assumed at the model top (vertical grid index k=nzt on the w-grid), with negative values of z indicating the depth.
  • Initial profiles are constructed (e.g. from pt_vertical_gradient / pt_vertical_gradient_level) starting from the sea surface, using surface values given by pt_surface, sa_surface, ug_surface, and vg_surface.
  • Zero salinity flux is used as default boundary condition at the bottom of the sea.
  • If switched on, random perturbations are by default imposed to the upper model domain from zu(nzt*2/3) to zu(nzt-3).

Relevant parameters to be exclusively used for steering ocean runs are bc_sa_t, bottom_salinityflux, sa_surface, sa_vertical_gradient, sa_vertical_gradient_level, and top_salinityflux.

Section 4.4.2 gives an example for appropriate settings of these and other parameters neccessary for ocean runs.

ocean = .T. does not allow settings of timestep_scheme = 'leapfrog' or 'leapfrog+euler' as well as scalar_advec = 'ups-scheme' .

[=#<insert_parameter_name> <insert_parameter_name>]

<insert type>

<insert value>

<insert explanation>


Grid:

Parameter Name Type Default Value Explanation

[=# ']

[=#<insert_parameter_name> <insert_parameter_name>]

<insert type>

<insert value>

<insert explanation>


Numerics:

Parameter Name Type Default Value Explanation

[=# ']

[=#<insert_parameter_name> <insert_parameter_name>]

<insert type>

<insert value>

<insert explanation>


Boundary conditions:

Parameter Name Type Default Value Explanation

bc_e_b

C*20

'neumann'

Bottom boundary condition of the TKE.

bc_e_b may be set to 'neumann' or '(u*)**2+neumann' . bc_e_b = 'neumann' yields to e(k=0)=e(k=1) (Neumann boundary condition), where e(k=1) is calculated via the prognostic TKE equation. Choice of '(u*)**2+neumann' also yields to e(k=0)=e(k=1), but the TKE at the Prandtl-layer top (k=1) is calculated diagnostically by e(k=1)=(us/0.1)2. However, this is only allowed if a Prandtl-layer is used (#prandtl_layer). If this is not the case, a warning is given and bc_e_b is reset to 'neumann' .

At the top boundary a Neumann boundary condition is generally used: (e(nz+1) = e(nz)).

[=#<insert_parameter_name> <insert_parameter_name>]

<insert type>

<insert value>

<insert explanation>


Initialization:

Parameter Name Type Default Value Explanation

[=# ']

[=#<insert_parameter_name> <insert_parameter_name>]

<insert type>

<insert value>

<insert explanation>


Topography:

Parameter Name Type Default Value Explanation

topography

C*40

'flat'

Topography mode.

The user can choose between the following modes:

'flat'

Flat surface.

'single_building'

Flow around a single rectangular building mounted on a flat surface. The building size and location can be specified by the parameters building_height, building_length_x, building_length_y, building_wall_left and building_wall_south.

'single_street_canyon'

Flow over a single, quasi-2D street canyon of infinite length oriented either in x- or in y-direction. The canyon size, orientation and location can be specified by the parameters canyon_height plus either canyon_width_x and canyon_wall_left or canyon_width_y and canyon_wall_south.

'read_from_file'

Flow around arbitrary topography. This mode requires the input file TOPOGRAPHY_DATA. This file contains the arbitrary topography height information in m. These data must exactly match the horizontal grid.

Alternatively, the user may add code to the user interface subroutine user_init_grid to allow further topography modes. These require to explicitly set the topography_grid_convention to either 'cell_edge' or 'cell_center' .

Non-flat topography modes may assign a kinematic sensible wall_heatflux and a kinematic wall_humidityflux (requires humidity = .T.) or a wall_scalarflux (requires passive_scalar = .T.) at the five topography faces.

All non-flat topography modes require the use of momentum_advec = scalar_advec = 'pw-scheme' , psolver /= 'sor' , alpha_surface = 0.0, galilei_transformation = .F., cloud_physics = .F., cloud_droplets = .F., and prandtl_layer = .T..

Note that an inclined model domain requires the use of topography = 'flat' and a nonzero alpha_surface.

[=#<insert_parameter_name> <insert_parameter_name>]

<insert type>

<insert value>

<insert explanation>


Canopy:

Parameter Name Type Default Value Explanation

[=# ']

[=#<insert_parameter_name> <insert_parameter_name>]

<insert type>

<insert value>

<insert explanation>


Others:

Parameter Name Type Default Value Explanation

[=# ']

[=#<insert_parameter_name> <insert_parameter_name>]

<insert type>

<insert value>

<insert explanation>

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