can boundary values change in "specified" boundary condition

Discuss the nesting capability within the model itself and any problems you might have run into.

can boundary values change in "specified" boundary condition

Postby Eli.Tziperman » Sun Mar 15, 2009 9:44 am

hello, this might be a silly question...: is it possible for feedback=1 in the namelist to allow changes in the boundary values when running with a single grid and with "specified" boundary conditions? can anything else lead to a boundary value changes with these boundary conditions? we are seeing such changes of values of prognostic variables on the boundaries and cannot figure out what causes this... thanks for any clues, Eli
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Re: can boundary values change in "specified" boundary condi

Postby samsonhagos » Fri Feb 10, 2012 12:34 pm

Hi Eli or anyone else,
Have you figured out why the specified boundary value were changing. I am having the same problem. I am trying to run wrf with cam boundary conditions and I tried to have 16 point buffer zone with 8 specified and 8 relaxing. But I see values in the specified region vary wildly causing cfl errors. Aren't they supposed to be not affected by the model at all?
Thank you,
Samson,
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Re: can boundary values change in "specified" boundary condi

Postby jimmyc » Sat Feb 11, 2012 10:22 am

If I recall physics is not turned off on the lateral boundary. Can you output physics tendencies and see if they are causing some of these issues. It might be that physics is only turned off on the outermost row/column of the "specified" zone. I should caution, however, that I have not actually looked at the code.

This could also be a problem if the interior solution starts to go astray between the specified and relaxed zone (i.e. from the dynamics).
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James Correia, Jr
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