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ROMS/TOMS

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PostPosted: Sat Sep 07, 2013 3:52 pm 
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Joined: Fri Dec 28, 2012 5:44 am
Posts: 28
Location: National Marine Environmental Forecasting Center
hi
when i try to compute normalization factors by using standard deviations, it comes up,
AD_DEF_HIS - creating adjoint file :wc13_adj.nc
forrtl: severe(174):seigsegv, sementation fault occurred

Then i page up the log file, before that, it has had prompted,
unsupported option in adjoint_based algorithms : BULK_FLUXES REASON: not working, warning
Does anyone come into this situation and tell me how to handle this problems?
--zongchen


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PostPosted: Mon Sep 09, 2013 2:11 am 
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Joined: Wed Feb 26, 2003 4:41 pm
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Location: IMCS, Rutgers University
The BULK_FLUXES option is not supported in the tangent linear and adjoint models. This is what the error says :!: The bulk fluxes routine is not continuously differentiable and not easy to adjoint. We did it anyways and the solution is very unstable because of nonlinearities. The same goes for vertical mixing parametrizations. These algorithms are highly nonlinear and very unstable in the tangent linear models (TLM, RPM). This is well documented in the literature. We use different strategy. These schemes are only used in the forward nonlinear model (NLM) trajectory that it is used to linearize the tangent linear and adjoint models.

Notice that we use FORWARD_MIXING, see the tutorials for 4D-Var with the WC13 examples. We cannot teach you how to use this algorithms in this forum. You need to understand what you are doing and read the relevant literature.


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PostPosted: Mon Sep 09, 2013 4:44 am 
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Joined: Fri Dec 28, 2012 5:44 am
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Location: National Marine Environmental Forecasting Center
hi arango
Thank u!
Normalization Factors for prior error correlations are computed for the unbalanced increments.I totally do the test according to what 4DVar_turorial_9 says, but failed.U say "We use different strategy".That is to say wc13_nrm_*.nc in Data file is not computed as the turorial_9's instructions, right?
what i want to do is copying your group's experiments about WC13, so i can learn technological process about 4d_Var algorithm step by step.
Actually, my study is about storm surge modeling and ROMS_2D can simulate storm surge well in a short time as i see. In other words, vertical mixing can be shut down, as well as BULk_FLUXES. So if i shut down all cppdefs about vertical mixing and BULk_FLUXES, of course including SOLVE3D in the head file when i run Error covariance model, that will be ok?
--zongchen


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PostPosted: Tue Sep 10, 2013 2:23 pm 
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Joined: Fri Dec 28, 2012 5:44 am
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Location: National Marine Environmental Forecasting Center
i think i almost know sth. Actually, normalization factors have been computed successfully. As to wc13_adj, it does have some problems like arango said. It needs more computation technics.


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PostPosted: Wed Jan 20, 2016 8:09 am 
wangzc wrote:
i think i almost know sth. Actually, normalization factors have been computed successfully. As to wc13_adj, it does have some problems like arango said. It needs more computation technics.

hello, wangzc, I met the same error like yours, would you like share your solution, many thanks in advance


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