[Wrf-users] different problems with nesting in WRF-NMM

Feng Liu fliu at mag.maricopa.gov
Mon May 4 10:58:18 MDT 2009

Dear Eduardo Penabad,
my possible answer to problem (1): You may check down-scale options in
WRFV3/share/interp_fcn.F for your needs. (2): For the coarsest domain,
parent_id should be set to 1 other than 0. You may ensure your domain
specifications are not illegal, for example, by plotgrids.exe.  Hope it
is helpful.


From: wrf-users-bounces at ucar.edu [mailto:wrf-users-bounces at ucar.edu] On
Behalf Of Eduardo Penabad Ramos
Sent: Friday, April 24, 2009 4:52 AM
To: 'wrfhelp'; wrf-users at ucar.edu
Cc: numerico at meteogalicia.es
Subject: [Wrf-users] different problems with nesting in WRF-NMM

Dear users,
In my institution, we are testing NMM core of WRF in order to use it in
some of our operational tasks. In this early stage of implementation in
our computing environment we are facing with some troubles. Here they
come a couple of them:
 (1) Static fields resolution at nested grids:
     WRF static fields in nested grid outputs (i.e. LU_INDEX, LANDMASK,
etc in wrfout_d02 file) look like they have the coarser (d01)
resolution. I mean, this fields have values with d02 resolution, but
this values are diamond-shaped seeming to be just a downscaling of d01
fields. The question is.... does WRF model use those fields written in
the wrfout file or does it use those written in the geo_nmm.nest.l01.nc
file? if this were the case, why WRF model doesn't dump the
high-resolution fields in wrfout file?
 (2) Nested domain too close to the boundary of parent (WRF says):
    We are running  (let's say, trying to run) a 3 nests configuration
(d01 @ 36km, d02 @ 12 km and d03 @ 4 km) with the namelist.input domains
data attached below. With i,j_parent_start values for d03 (56,76) and
d02 e_we and e_sn values  (121,196) one should expect that a d03 grid
with e_we=82 and e_sn=182 will run, but I'm getting this error. Am I
doing something wrong? 
 -------------- FATAL CALLED ---------------
namelist.input details:
 time_step                           = 90,
 time_step_fract_num                 = 0,
 time_step_fract_den                 = 7,
 max_dom                             = 3,
 e_we                                = 84,      121, 82
 e_sn                                = 150,     196, 182
 e_vert                              = 28,       28, 28
 num_metgrid_levels                  = 27,
 dx                                  = .233211
 dy                                  = .228236
 p_top_requested                     = 5000.
 ptsgm                               = 42000.,
 grid_id                             = 1,        2, 3
 parent_id                           = 0,        1, 2
 i_parent_start                      = 1,        32, 56
 j_parent_start                      = 1,        38, 76
 parent_grid_ratio                   = 1,        3, 3
 parent_time_step_ratio              = 1,        3, 3
Thanks in advance for your help!
Eduardo Penabad
NWP Department. MeteoGalicia
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