| 266 | | If this parameter is specified, both in the 1d and in the 3d-model constant values for the eddy diffusivities are used in space and time with K,,m,, = '''km_constant''' and K,,h,, = K,,m,, / [#prandtl_number prandtl_number]. The prognostic equation for the subgrid-scale TKE is switched off. Constant eddy diffusivities are only allowed with the Prandtl layer ([#prandtl_layer prandtl_layer]) switched off. |
| | 266 | If this parameter is specified, both in the 1d and in the 3d-model constant values for the eddy diffusivities are used in space and time with K,,m,, = '''km_constant''' and K,,h,, = K,,m,, / [#prandtl_number prandtl_number]. The prognostic equation for the subgrid-scale TKE is switched off. Constant eddy diffusivities are only allowed with the constant flux layer ([#constant_flux_layer constant_flux_layer]) switched off. |
| 1538 | | Parameter to switch on a Prandtl layer.\\\\ |
| 1539 | | By default, a Prandtl layer is switched on at the bottom boundary between z = 0 and z = 0.5 * [#dz dz] (the first computational grid point above ground for u, v and the scalar quantities). In this case, at the bottom boundary, free-slip conditions for u and v (see [#bc_uv_b bc_uv_b]) are not allowed. Likewise, laminar simulations with constant eddy diffusivities ([#km_constant km_constant]) are forbidden.\\\\ |
| 1540 | | With Prandtl-layer switched off, the pressure boundary condition [#bc_p_b bc_p_b] = '' 'neumann+inhomo' '' is not allowed.\\\\ |
| 1541 | | If the Prandtl-layer is switched off and fluxes shall be prescribed at the surface (by setting [#surface_heatflux surface_heatflux]), it is required to set the parameter [#use_surface_fluxes use_surface_fluxes] = ''.T.''.\\\\ |
| | 1538 | Parameter to switch on a constant flux layer at the bottom boundary.\\\\ |
| | 1539 | By default, a constant flux layer is switched on at the bottom boundary between z = 0 and z = 0.5 * [#dz dz] (the first computational grid point above ground for u, v and the scalar quantities). In this case, at the bottom boundary, free-slip conditions for u and v (see [#bc_uv_b bc_uv_b]) are not allowed. Likewise, laminar simulations with constant eddy diffusivities ([#km_constant km_constant]) are forbidden.\\\\ |
| | 1540 | With a constant flux layer switched off at the bottom, the pressure boundary condition [#bc_p_b bc_p_b] = '' 'neumann+inhomo' '' is not allowed.\\\\ |
| | 1541 | If the constant flux layer is switched off and fluxes shall be prescribed at the surface (by setting [#surface_heatflux surface_heatflux]), it is required to set the parameter [#use_surface_fluxes use_surface_fluxes] = ''.T.''.\\\\ |
| 1576 | | [=#rif_max '''rif_max'''] |
| 1577 | | }}} |
| 1578 | | {{{#!td style="vertical-align:top" |
| 1579 | | R |
| 1580 | | }}} |
| 1581 | | {{{#!td style="vertical-align:top" |
| 1582 | | 1.0 |
| 1583 | | }}} |
| 1584 | | {{{#!td |
| 1585 | | Upper limit of the flux-Richardson number.\\\\ |
| 1586 | | With the Prandtl layer switched on (see [#prandtl_layer prandtl_layer]), flux-Richardson numbers ('''rif''') are calculated for z=zp (k=1) in the 3d-model (in the [../../tec/1dmodel 1d-model] for all heights). Their values in particular determine the values of the friction velocity (1d- and 3d-model) and the values of the eddy diffusivity (1d-model). With small wind velocities at the Prandtl layer top or small vertical wind shears in the 1d-model, '''rif''' can take up unrealistic large values. They are limited by an upper ('''rif_max''') and lower limit (see [#rif_min rif_min]) for the flux-Richardson number. The condition '''rif_max''' > rif_min must be met. |
| 1587 | | }}} |
| 1588 | | |---------------- |
| 1589 | | {{{#!td style="vertical-align:top" |
| 1590 | | [=#rif_min '''rif_min'''] |
| 1591 | | }}} |
| 1592 | | {{{#!td style="vertical-align:top" |
| 1593 | | R |
| 1594 | | }}} |
| 1595 | | {{{#!td style="vertical-align:top" |
| 1596 | | -5.0 |
| 1597 | | }}} |
| 1598 | | {{{#!td |
| 1599 | | Lower limit of the flux-Richardson number.\\\\ |
| 1600 | | For further explanations see [#rif_max rif_max]. The condition rif_max > '''rif_min''' must be met. |
| 1601 | | }}} |
| 1602 | | |---------------- |
| 1603 | | {{{#!td style="vertical-align:top" |
| 1668 | | If no surface heat flux is assigned, '''shf''' is calculated at each timestep by u,,*,, {{{*}}} theta,,*,, (of course only with [#prandtl_layer prandtl_layer] switched on). Here, u,,*,, and theta,,*,, are calculated from the Prandtl law assuming logarithmic wind and temperature profiles between k=0 and k=1. In this case a Dirichlet condition (see [#bc_pt_b bc_pt_b]) must be used as bottom boundary condition for the potential temperature.\\\\ |
| | 1640 | If no surface heat flux is assigned, '''shf''' is calculated at each timestep by u,,*,, {{{*}}} theta,,*,, (of course only with [#constant_flux_layer constant_flux_layer] switched on). Here, u,,*,, and theta,,*,, are calculated from Monin-Obukhov similarity theory assuming logarithmic wind and temperature profiles between k=0 and k=1. In this case a Dirichlet condition (see [#bc_pt_b bc_pt_b]) must be used as bottom boundary condition for the potential temperature.\\\\ |
| 1686 | | If no surface scalar flux is assigned ('''surface_scalarflux''' = ''0.0''), it is calculated at each timestep by u,,*,, {{{*}}} s,,*,, (of course only with [#prandtl_layer prandtl_layer] switched on). Here, s,,*,, is calculated from the Prandtl law assuming a logarithmic scalar concentration profile between k=0 and k=1. In this case a Dirichlet condition (see bc_s_b) must be used as bottom boundary condition for the scalar concentration. |
| | 1658 | If no surface scalar flux is assigned ('''surface_scalarflux''' = ''0.0''), it is calculated at each timestep by u,,*,, {{{*}}} s,,*,, (of course only with [#constant_flux_layer constant_flux_layer] switched on). Here, s,,*,, is calculated from Monin-Obukhov similarity theory assuming a logarithmic scalar concentration profile between k=0 and k=1. In this case a Dirichlet condition (see bc_s_b) must be used as bottom boundary condition for the scalar concentration. |
| 1702 | | If no surface water flux is assigned ('''surface_waterflux''' = ''0.0''), it is calculated at each timestep by u,,*,, {{{*}}} q,,*,, (of course only with Prandtl layer switched on). Here, q,,*,, is calculated from the Prandtl law assuming a logarithmic temperature profile between k=0 and k=1. In this case a Dirichlet condition (see bc_q_b) must be used as the bottom boundary condition for the humidity. |
| | 1674 | If no surface water flux is assigned ('''surface_waterflux''' = ''0.0''), it is calculated at each timestep by u,,*,, {{{*}}} q,,*,, (of course only with a constant flux layer switched on). Here, q,,*,, is calculated from Monin-Obukhov similarity theory assuming a logarithmic temperature profile between k=0 and k=1. In this case a Dirichlet condition (see bc_q_b) must be used as the bottom boundary condition for the humidity. |
| 1833 | | By default, the near-surface subgrid-scale fluxes are parameterized (like in the remaining model domain) using the gradient approach. If '''use_surface_fluxes''' = ''.T.,'' the user-assigned surface fluxes are used instead (see [#surface_heatflux surface_heatflux], [#surface_waterflux surface_waterflux] and [#surface_scalarflux surface_scalarflux]) or the surface fluxes are calculated via the Prandtl layer relation (depends on the bottom boundary conditions, see [#bc_pt_b bc_pt_b], [#bc_q_b bc_q_b] and [#bc_s_b bc_s_b]).\\\\ |
| 1834 | | '''use_surface_fluxes''' is automatically set ''.T.,'' if a Prandtl layer is used (see [#prandtl_layer prandtl_layer]).\\\\ |
| 1835 | | The user may prescribe the surface fluxes at the bottom boundary without using a Prandtl layer by setting '''use_surface_fluxes''' = ''.T.'' and [#prandtl_layer prandtl_layer] = ''.F.''. If , in this case, the momentum flux (u,,*,,^2^) should also be prescribed, the user must assign an appropriate value within the [../userint user-defined code]. |
| | 1805 | By default, the near-surface subgrid-scale fluxes are parameterized (like in the remaining model domain) using the gradient approach. If '''use_surface_fluxes''' = ''.T.,'' the user-assigned surface fluxes are used instead (see [#surface_heatflux surface_heatflux], [#surface_waterflux surface_waterflux] and [#surface_scalarflux surface_scalarflux]) or the surface fluxes are calculated via Monin-Obukhov similarity theory (depends on the bottom boundary conditions, see [#bc_pt_b bc_pt_b], [#bc_q_b bc_q_b] and [#bc_s_b bc_s_b]).\\\\ |
| | 1806 | '''use_surface_fluxes''' is automatically set ''.T.,'' if a constant flux layer is used (see [#constant_flux_layer constant_flux_layer]).\\\\ |
| | 1807 | The user may prescribe the surface fluxes at the bottom boundary without using a constant flux layer by setting '''use_surface_fluxes''' = ''.T.'' and [#constant_flux_layer constant_flux_layer] = ''.F.''. If , in this case, the momentum flux (u,,*,,^2^) should also be prescribed, the user must assign an appropriate value within the [../userint user-defined code]. |
| 2011 | | The arrays of the 3d-model are initialized with the (stationary) solution of the [../../tec/1dmodel 1d-model]. These are the variables e, K,,h,,{{{,}}} K,,m,,{{{,}}} u, v and with Prandtl layer switched on rif, us, usws, vsws. The temperature (humidity) profile consisting of linear sections is set as for '' 'set_constant_profiles' '' and assumed as constant in time within the 1d-model. For steering of the 1d-model a set of parameters with suffix "_1d" (e.g. [#end_time_1d end_time_1d], [#damp_level_1d damp_level_1d]) is available.\\\\ |
| | 1983 | The arrays of the 3d-model are initialized with the (stationary) solution of the [../../tec/1dmodel 1d-model]. These are the variables e, K,,h,,{{{,}}} K,,m,,{{{,}}} u, v and with a constant flux layer switched on ol, us, usws, vsws. The temperature (humidity) profile consisting of linear sections is set as for '' 'set_constant_profiles' '' and assumed as constant in time within the 1d-model. For steering of the 1d-model a set of parameters with suffix "_1d" (e.g. [#end_time_1d end_time_1d], [#damp_level_1d damp_level_1d]) is available.\\\\ |
| | 2781 | |---------------- |
| | 2782 | {{{#!td style="vertical-align:top" |
| | 2783 | [=#zeta_max '''zeta_max'''] |
| | 2784 | }}} |
| | 2785 | {{{#!td style="vertical-align:top" |
| | 2786 | R |
| | 2787 | }}} |
| | 2788 | {{{#!td style="vertical-align:top" |
| | 2789 | 20.0 |
| | 2790 | }}} |
| | 2791 | {{{#!td |
| | 2792 | Upper limit of the stability parameter {{{[zeta = z_mo/L}}}, with {{{z_mo}}} being the height of the constant flux layer, and {{{L}}} being the Obukhov length.\\\\ |
| | 2793 | With a constant flux layer switched on (see [#constant_flux_layer constant_flux_layer]), the Obukhov length ('''ol''') is calculated for {{{z=z_mo (k=1)}}} in the 3d-model (in the [../../tec/1dmodel 1d-model] for all heights) for each horizontal grid point. Its particular values determine the values of the friction velocity (1d- and 3d-model) and the values of the eddy diffusivity (1d-model). With small wind velocities at the top of the constant flux layer or small vertical wind shears in the 1d-model, the stability parameter '''zeta = z_mo/ol''' can take up unrealistic values. They are limited by an upper ('''zeta_max''') and lower limit (see [#zeta_min zeta_min]). The condition '''zeta_max''' > zeta_min must be met. |
| | 2794 | }}} |
| | 2795 | |---------------- |
| | 2796 | {{{#!td style="vertical-align:top" |
| | 2797 | [=#zeta_min '''zeta_min'''] |
| | 2798 | }}} |
| | 2799 | {{{#!td style="vertical-align:top" |
| | 2800 | R |
| | 2801 | }}} |
| | 2802 | {{{#!td style="vertical-align:top" |
| | 2803 | -9990.0 |
| | 2804 | }}} |
| | 2805 | {{{#!td |
| | 2806 | Lower limit of the stability parameter {{{[zeta = z_mo/L}}}, with {{{z_mo}}} being the height of the constant flux layer, and {{{L}}} being the Obukhov length.\\\\ |
| | 2807 | For further explanations see [#zeta_max zeta_max]. The condition zeta_max > '''zeta_min''' must be met. |
| | 2808 | }}} |
