=== Runs with large scale forcing and nudging ===

Using nudging in a PALM simulation requires to provide nudging and large scale forcing data in external files. The file names should have the endings _nudge and _lsf respectively. They have to be placed in the INPUT directory on the host where the simulation will run. The layout of the data in the files is described in [../../iofiles#NUDGING_DATA NUDGING_DATA] and [../../iofiles#LSF_DATA LSF_DATA] respectively. In addition, the PALM configuration file .mrun.config has to be extended for the following two lines
{{{
...
#----------------------------------------------------------------------------
# List of input-files
#----------------------------------------------------------------------------
...
NUDGING_DATA             in:locopt     d3#:d3f  $base_data/$fname/INPUT    _nudge
LSF_DATA                 in:locopt     d3#:d3f  $base_data/$fname/INPUT    _lsf
...
}}}

With the following parameter file nudge_CBL_p3d a simulation with nudging can be performed. The nudging and large scale forcing data originate from a [http://cosmo-model.org/ COSMO] simulation of the 5th May, 2013, 9-15UTC. During this time a convective boundary layer with shallow cumulus clouds form.
{{{
 &inipar nx = 191, ny = 191, nz = 64,
         dx = 50.0, dy = 50.0, dz = 50.0,

         fft_method = 'fftw',

         humidity = .T., cloud_physics= .T.,

         nudging = .T.,

         large_scale_forcing = .T.,

         momentum_advec = 'ws-scheme',
         scalar_advec   = 'ws-scheme',

         initializing_actions = 'set_constant_profiles',

         bc_uv_b = 'dirichlet',
	 bc_pt_b = 'neumann',
	 bc_q_b  = 'neumann',

         phi = 50.92,

         pt_reference = 290.0,
         reference_state = 'single_value', 

         prandtl_layer = .T.,
         use_surface_fluxes = .T., 
         roughness_length = 0.01,

         rayleigh_damping_factor = 0.05,
         rayleigh_damping_height = 2700.0,
         scalar_rayleigh_damping = .T., /


 &d3par  end_time = 21600.0, 

         termination_time_needed = 300.0,

         npex = 64,
         npey = 1, 

         create_disturbances = .T.,

         netcdf_data_format = 2,

         dt_run_control = 30.0,
         dt_dots        = 30.0,

         dt_dopr = 1800.0,
         averaging_interval_pr = 1800.0, 
         dt_averaging_input_pr = 30.0,

         data_output_pr = '#u','#v','w','#pt','ug','vg',
                          '#lpt','#q','#qv','ql',
                          'e','e*','p','#km','#kh','#l',
                          'w"u"','w*u*','wu', 'w"v"','w*v*','wv',
                          'w"pt"', 'w*pt*', 'wpt', 
                          'w"vpt"', 'w*vpt*', 'wvpt', 
                          'w"q"', 'w*q*', 'wq', 
                          'w"qv"', 'w*qv*', 'wqv', 
                          'w*e*', 'u*2', 'v*2', 'w*2', 'pt*2', 'q*2',
                          'w*3', 'Sw', 'w*2pt*', 'w*pt*2',
                          'w*u*u*:dz','w*p*:dz', 'w"e:dz', 'hyp',

         data_output = 'u', 'v', 'w', 'pt', 'lpt', 'p', 'q', 'ql'
                       'u_xy', 'v_xy', 'w_xy', 'pt_xy', 'lpt_xy',
                       'p_xy', 'q_xy', 'ql_xy', 
                       'u_xz', 'v_xz', 'w_xz', 'pt_xz', 'lpt_xz',
                       'p_xz', 'q_xz', 'ql_xz', 
                       'shf*_xy', 'qsws*_xy', 'lwp*_xy',

         nz_do3d = 32, 

         dt_do3d        = 3600.0,
         dt_do2d_xy     = 3600.0,
         dt_do2d_xz     = 3600.0,
         dt_data_output = 3600.0,

         do2d_at_begin = .T., !->check perturbations

         section_xy = 2, 4, 10, 15, 20, 25,  
         section_xz = 96,

         data_output_2d_on_each_pe = .T.,  /
}}}
The external files [[attachment:nudge_CBL_nudge|nudge_CBL_nudge]] [[attachment:nudge_CBL_lsf|nudge_CBL_lsf]] are attached. The nudging time scale tau is 6 hours and the nudging is performed in the whole model domain (boundary layer and free atmosphere).