[Wrf-users] grid scale noises

[zpazandeh at civeng.adelaide.edu.au]

Hi


I had a run with following namelist and in outputs I am observing some
grid scale noises, I've been told to decrease the time step and turning on
the diff_6th_opt=2, I have done so and the noises are much less but
haven't resolve totally rather has shifted from inland to over water.

I don't have any idea what to do next.




> &domains
> time_step                       = 120,
> time_step_fract_num      = 0,
> time_step_fract_den       = 1,
> max_dom                      = 3,
> e_we                            = 126,      129,      139,      91,
> e_sn                             = 109,      165,      172,      136,
> e_vert                           = 35,       35,       35,        35,
> p_top_requested            = 5000,
> num_metgrid_levels       = 27,
> num_metgrid_soil_levels  = 2,
> dx                                = 28800, 7200, 2400,  800,
> dy                               = 28800, 7200, 2400,  800,
> grid_id                        = 1,        2,        3,        4,
> parent_id                    = 1,        1,        2,        3,
> i_parent_start             = 1,       28,       58,       82,
> j_parent_start             = 1,       38,       45,       46,
> parent_grid_ratio         = 1,        4,        3,        3,
> parent_time_step_ratio   = 1,        4,        3,        3,
> feedback                 = 1,
> smooth_option            = 0,
> eta_levels
> =1,0.999,0.998,0.993,0.989,0.985,0.980,0.977,0.973,0.968,0.964,0.946,0.922,0.894,0.860,0.817,0.766,0.707,0.644,0.576,0.507,0.444,0.380,0.324,0.273,0.228,0.188,0.152,0.121,0.0930,0.0690,0.0480,0.0290,0.0140,0,
>
> /
>
> &physics
> mp_physics                = 3,        3,        3,        3,
> ra_lw_physics             = 3,        3,        3,        3,
> ra_sw_physics            = 1,        1,        1,        1,
> radt                           = 2,        2,        2,        2,
> sf_sfclay_physics        = 2,        2,        2,        2,
> sf_surface_physics      = 2,        2,        2,        2,
> bl_pbl_physics           = 2,        2,        2,        2,
> bldt                           = 0,        0,        0,        0,
> cu_physics                = 1,        1,        1,        1,
> cudt                        = 0,        0,        0,        0,
> isfflx                   = 1,
> ifsnow                   = 1,
> icloud                   = 1,
> surface_input_source     = 1,
> num_soil_layers          = 4,
> num_land_cat             = 33,
> sf_urban_physics         = 2,        2,        2,        2,
> maxiens                  = 1,
> maxens                   = 3,
> maxens2                  = 3,
> maxens3                  = 16,
> ensdim                   = 144,
> sst_update              =1,
> /
>
> &fdda
> /
>
> &dynamics
> w_damping                = 0,
> diff_opt                 = 1,
> km_opt                   = 4,
> diff_6th_opt             = 0,        0,        0,        0,
> diff_6th_factor          = 0.12,     0.12,     0.12,     0.12,
> base_temp                = 290.,
> damp_opt                 = 3,
> zdamp                    = 5000.,    5000.,    5000.,    5000.,
> dampcoef                 = 0.01,     0.01,     0.01,     0.01,
> khdif                    = 0,        0,        0,        0,
> kvdif                    = 0,        0,        0,        0,
> non_hydrostatic          = .true.,   .true.,   .true.,   .true.,
> moist_adv_opt            = 1,        1,        1,        1,
> scalar_adv_opt           = 1,        1,        1,        1,
> /
>
> &bdy_control
> spec_bdy_width           = 5,
> spec_zone                = 1,
> relax_zone               = 4,
> specified                = .true.,  .false.,  .false.,  .false.,
> nested                   = .false.,   .true.,   .true.,   .true.,


Thanks in advance
Mina