1783 | | If [#turbulent_inflow turbulent_inflow] = .TRUE., two recycling methods for the thermodynamic quantities theta and q are available:\\\\ |
1784 | | |
1785 | | 'turbulent_fluctuation': Turbulent fluctuations of theta (and q if humidity = .TRUE.) are recycled and added to the inflow profile, see [#turbulent_inflow turbulent_inflow] for a detailed description. This method is the default method and is also used for all other prognostic quantities. If surface heating/cooling or a surface waterflux is applied, a horizontal temperature (humidity) gradient inside the boundary layer will develop, because the temperature/humidity profiles at the inflow are constant. The resulting horizontal differences in buoyancy can trigger an undesired circulation inside the entire domain and instabilities at the inflow boundary (see [#pt_damping_factor pt_damping_factor]).\\\\ |
1786 | | |
1787 | | 'absolute_value': The absolute instantaneous values of theta (and q if humidity = .TRUE.) are recycled, so that the potential temperature (humidity) values at the inflow boundary and the recycling plane are identical. With this method there is no horizontal temperature (humidity) gradient and thus the circulation and the instabilities at the inflow boundary will not occur. Note that the mean inflow profile of the potential temperature (humidity) will now change in time (growing boundary layer), in contrast to the inflow profile of all other quantities (e.g. u,v,w) that are constant. In order to avoid this mismatch, the boundary layer height should be kept constant by applying a [#large_scale_subsidence large_scale_subsidence] to scalar quantities. |
| 1783 | If [#turbulent_inflow turbulent_inflow] = .TRUE., three recycling methods are available:\\\\ |
| 1784 | |
| 1785 | 'turbulent_fluctuation': Turbulent fluctuations of all prognostic variables are recycled and added to the inflow profile, see [#turbulent_inflow turbulent_inflow] for a detailed description. This method is the default method. If surface heating/cooling or a surface waterflux is applied, a horizontal temperature (humidity) gradient inside the boundary layer will develop, because the temperature/humidity profiles at the inflow are constant. The resulting horizontal differences in buoyancy can trigger an undesired circulation inside the entire domain and instabilities at the inflow boundary (see [#pt_damping_factor pt_damping_factor]).\\\\ |
| 1786 | |
| 1787 | 'absolute_value': The absolute instantaneous values of all prognostic variables but vertical velocity are recycled, so that the values at the inflow boundary and the recycling plane are identical (for vertical velocity, still only the turbulent fluctuations are recycled). With this method there is no horizontal temperature (humidity) gradient and thus the circulation and the instabilities at the inflow boundary will not occur. Note that the mean inflow profiles of all prognostic variables but vertical velocity will now change in time (growing boundary layer).\\\\ |
| 1788 | |
| 1789 | 'absolute_value_thermodynamic_quantities': The absolute instantaneous values of potential temperature and (if present) humidity are recycled. For all other prognostic variables the turbulent fluctuations are recycled. With this method there is no horizontal temperature (humidity) gradient and thus the circulation and the instabilities at the inflow boundary will not occur. Note that the mean inflow profiles of potential temperature (humidity) will now change in time (growing boundary layer), in contrast to the inflow profile of all other quantities (e.g. u,v,w) that are constant. In order to avoid this mismatch, the boundary layer height should be kept constant by applying a [#large_scale_subsidence large_scale_subsidence] to scalar quantities. |