[Wrf-users] Vertical levels problem with urban canopy model

[Agnes Mika]

Dear WRF help and WRF users,

 We have recently set up our WRF V3.1.1 to run with two extra vertical
 levels. These levels were added in order to be able to extract data
 at 50 and 70 m altitudes without needing to interpolate too much.

 For a while the model was running just fine but now I am getting the
 following error messages in the rsl.out files:

         Warning ZR + 2m  is larger than the 1st WRF level

 This error seems to be generated by the urban canopy model
 (module_sf_urban) and it seems to occur when the roof level/building
 height is above the lowest model level. 

 I took a look in the technical documentation of the UCM, it says: "In
 the UCM, all the urban effects in the vertical are assumed to be
 subgrid scale meaning that the urban processes ar occurring below the
 lowest model level."

 Apart from the obvious (changing the vertical level structure or
 turning the UCM off) is there a way to solve this problem? Any help
 is appreciated.

 I copy below the relevant parts of my namelist.input:

 &domains
 time_step                           = 240,
 time_step_fract_num                 = 0,
 time_step_fract_den                 = 1,
 max_dom                             = MAXDOM,
 grid_id                             = 1,     2,     3, 4,     5,     6,
 parent_id                           =   0,   1,   2,   2,   2,   2
 parent_grid_ratio                   =   1,   3,   3,   3,   3,   3,
 i_parent_start                      =   1,  53,   96,   55,   100,   100,
 j_parent_start                      =   1,  23,   24,   58,   100,   100,
 e_we                                =   144,  181,   181,  101,   100,  100,
 e_sn                                =   106,  151,   142,  101,   100,  100
 s_we                                =   1,     1,     1,   1,     1,     1,
 s_sn                                =   1,     1,     1,   1,     1,     1,
 s_vert                              =   1,     1,     1,   1,     1,     1,
 e_vert                              =  31,    31,    31,  31,    31,    31,
 num_metgrid_levels                  = 27,
 num_metgrid_soil_levels             = 4,
 eta_levels                          = 1.000, 0.995, 0.991, 0.987, 0.983, 0.977, 0.970, 0.954, 0.934, 0.909, 0.880, 0.830, 0.779, 0.729, 0.678, 0.592, 0.514, 0.443, 0.380, 0.324, 0.273, 0.228, 0.188, 0.153, 0.121, 0.094, 0.069, 0.048, 0.030, 0.014, 0.000,
 dx                                  = 27000, 9000,  3000, 1333.333333333, 1333.333333333,  1333,
 dy                                  = 27000, 9000,  3000, 1333.333333333, 1333.333333333,  1333,
 parent_id                           = 0,     1,     2, 3,     3,     3,
 parent_grid_ratio                   = 1,     3,     3, 3,     3,     3,
 parent_time_step_ratio              = 1,     3,     3, 3,     3,     3,
 feedback                            = 1,
 smooth_option                       = 0,
 use_adaptive_time_step              = .true.
 step_to_output_time                 = .true.
 target_cfl                          = 1.2, 1.2, 1.2, 1.2, 1.2, 1.2,
 max_step_increase_pct               = 5, 51, 51, 51, 51, 51,
 starting_time_step                  = 200, 67, 22, 9, -1, -1,
 min_time_step                       = -1, -1, -1, -1, -1, -1,
 max_time_step                       = 400, 134, 44, 18, -1, -1,
 /


 &physics
 mp_physics                          = 5,     5,     5, 5,     5,     5,
 ra_lw_physics                       = 1,     1,     1, 1,     1,     1,
 ra_sw_physics                       = 1,     1,     1, 1,     1,     1,
 radt                                = 30,    30,    30, 30,    30,    30,
 sf_sfclay_physics                   = 1,     1,     1, 1,     1,     1,
 sf_surface_physics                  = 2,     2,     2, 2,     2,     2,
 sf_urban_physics                    = 1,     1,     1, 1,     1,     1,
 bl_pbl_physics                      = 1,     1,     1, 1,     1,     1,
 bldt                                = 0,     0,     0, 0,     0,     0,
 cu_physics                          = 1,     1,     0, 0,     0,     0,
 cudt                                = 0,     0,     0, 0,     0,     0,
 isfflx                              = 1,
 ifsnow                              = 1,
 icloud                              = 1,
 surface_input_source                = 1,
 num_land_cat                        = 20,
 num_soil_layers                     = 4,
 mp_zero_out                         = 0,
 maxiens                             = 1,
 maxens                              = 3,
 maxens2                             = 3,
 maxens3                             = 16,
 ensdim                              = 144,
 /

Thank you in advance,
Agnes

--
Dr. A'gnes Mika
Advisor, Meteorology and Air Quality

Tel:    +31 (0)527-242299
Fax:    +31 (0)527-242016
Web:    www.bmtargoss.com

BMT ARGOSS
P.O. Box 61, 8325 ZH Vollenhove
Voorsterweg 28, 8316 PT Marknesse
The Netherlands

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