[Wrf-users] Re: Global WRF with nests and time-varying lower boundary conditions

[wrfhelp]

We definitely should put back interval_seconds and input_from_file  
options back to the provided namelist file. Thanks.

The last point is well appreciated. We will check to see if there is  
anything we can do about it.

wrfhelp

On Sep 4, 2008, at 10:44 AM, Eric Altshuler wrote:

> Hello,
>
> I am using WRF 3.0.1.1 to run global simulations with nests and time- 
> varying lower boundary conditions (sst_update = 1). I have found  
> that the namelist.input.global file provided in WRFV3/test/em_real  
> does not specify values for interval_seconds and input_from_file.  
> Two problems arise from the omission of these two namelist variables:
>
> 1. If interval_seconds is not specified, it defaults to 43200  
> seconds (12 h), and the wrflowinp_d* files only contain 12-hourly  
> lower boundary conditions even when I set the following:
>
> auxinput4_inname                    = "wrflowinp_d<domain>",
> auxinput4_interval                  = 360,  360,  360,
>
> So even when I request 6-hourly data for the lower boundary  
> condition file, I get 12-hourly output instead. Since I have a  
> global domain and lateral boundary conditions are unnecessary (and  
> wrfbdy_d01 is no longer produced in version 3.0.1.1), the value of  
> interval_seconds (which pertains to lateral boundary conditions, not  
> lower boundary conditions) shouldn't be relevant, but it still  
> overrides the value of auxinput4_interval for lower boundary  
> conditions.
>
> 2. If input_from_file is not specified, it defaults to .false. and  
> no wrfinput_d02 file is produced for domain 2. Also, no  
> wrflowinp_d02 is created. Apparently, if wrfinput and/or wrflowinp  
> files are desired for nests, then input_from_file has to be set  
> to .true. in namelist.input.global.
>
> Also, I discovered that the wrflowinp_d* files are identical  
> regardless of whether usemonalb is .true. or .false. Can someone  
> explain why this is the case?
>
> Finally, I intend to run a global domain with several nests and time- 
> varying SST and sea ice. For a global domain with CONSTANT lower  
> boundary conditions, it is only necessary to run WPS on the initial  
> data. However, if time-varying lower boundary conditions are  
> desired, then WPS must be run on the data for all times throughout  
> the simulation period (3, 6, 12-hourly or whatever). In truth, only  
> the lower boundary data (SST, sea ice) are required for multiple  
> times; since this is a global simulation, the full 3-D atmospheric  
> data are only really needed at the initial time, yet, as I  
> understand things, WPS (specifically metgrid) cannot produce a  
> met_em* file for a particular time if the 3-D meteorological data  
> are missing. Is there some way to run WPS so that the initial met_em  
> file contains all the 3-D and lower boundary data (as usual) but  
> subsequent met_em files contain only the necessary time-varying  
> lower boundary data (SST, sea ice, vegetation fraction and albedo)?
>
> Thanks in advance for your feedback.
>
> Best regards,
>
> Eric L. Altshuler