Re:_Re:_Re:_[MITgcm-support]_Advection_schemes

[Petter Stenström]

Hi Patrick,

Thanks for your reply. Noop, I did not forget to specify
tracerAdvScheme=33. The problem seems rather to be that multiDimAdv has to
be false when using scheme no 33. I looked again in the documentation and
found a note on that. 

The strange thing is that this seems to be required only for tr1, not for T
and S. I ran a simple experiment in a simple domain with exactly the same
initial distribution and concentration of T and tr1, and the same advection
scheme (33). tr1 goes to infinity, whereas T stays on realistic values.
Strange since tr1 seems to use the same diffusivity constants as T in the
default configuration. I will look closer in the code and try to figure out
what the difference between the two is.There are slight differences also
when using other schemes (I've tried 3rd order upwind biased).

/Petter



------- Original message -------
From: heimbach at MIT.EDU
Date: Wed, 18 Aug 2004 15:27:19 -0400

Hi Petter,

sorry I oversaw your reply
(I am CC-ing to mitgcm-support and suggest
that you always send to that list).

Re. your question I think you forgot to also specify
 tracerAdvScheme = 33
in your data file.
Can you try and see whether that gives the
desired results?

-Patrick



Quoting Petter StenstrXm <petters at kth.se>:

> Hi Patrick,
> 
> thanks. 33 is apparently a flux limited 3rd order DST. It works fine with
S
> and T, but not with a passive tracer. I cannot understand why, but false
> extrema appear in the TR1 field, but not in the S and T fields, when I use
> 33 for all of them. Is there an obvious explanation for this that I don't
> see?
> 
> Petter
> 
> ------- Original message -------
> From: heimbach at MIT.EDU
> Date: Tue, 17 Aug 2004 14:35:19 -0400
> 
> Hi Petter,
> 
> they are described in sections 2.16, 2.17
> http://mitgcm.org/sealion/online_documents/node71.html
> http://mitgcm.org/sealion/online_documents/node76.html
> of the online documentation,
> but for the actual number associated with each sheme
> you'll have to look in the header file
> pkg/generic_advdiff/GAD.h
> 
> -Patrick
> 
> 
> 
> Quoting Petter StenstrXm <petters at kth.se>:
> 
> > Hi!
> > 
> > Is there a list of all the different advection schemes available and
their
> > corresponding numbers? I cannot find any in the documentation.
> > 
> > I have been using advection scheme 33 for some time (which I thought
was a
> > flux limiter scheme), but when I look now, I cannot see that the value
33
> > is interpreted anywhere in the code.
> > 
> > Regards,
> > 
> > Petter Stenström
> > Dept of Land and Water Res Eng
> > Royal Institute of Technology
> > SE-100 44 Stockholm
> > Phone: +46 8 7908657
> > Email: petters at kth.se
> > 
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://dev.mitgcm.org/mailman/listinfo/mitgcm-support
> > 
> 
> 
> --------------------------------------------------------
> Patrick Heimbach   Massachusetts Institute of Technology
> FON: +1/617/253-5259                  EAPS, Room 54-1518
> FAX: +1/617/253-4464             77 Massachusetts Avenue
> mailto:heimbach at mit.edu               Cambridge MA 02139
> http://www.mit.edu/~heimbach/                        USA
> 
> 
> 
> 


--------------------------------------------------------
Patrick Heimbach   Massachusetts Institute of Technology
FON: +1/617/253-5259                  EAPS, Room 54-1518
FAX: +1/617/253-4464             77 Massachusetts Avenue
mailto:heimbach at mit.edu               Cambridge MA 02139
http://www.mit.edu/~heimbach/                        USA