Models, Methods, Software

AOLBGCM validation is an ongoing process.
Can’t ever do too much of it.

it is not even viscous dissipation. There is also an energy imbalance in the NASA/GISS ModelE code due to the error in the ‘viscous dissipation’. The energy imbalance is about the same magnitude as the imbalance associated with increased concentrations of CO2 in the atmosphere.

Updated January 14, 2009, down near the end.

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This post is a continuation of discussions of the modeling of viscous dissipation in GCMs. The issue has recently come up again over at Lucia’s Blog in this thread. The thread at Lucia’s is related to the posts on this Blog here, here, and here. I have also in the past commented on the issue at Climate Audit, Professor Pielke Sr.’s Climate Science, and Real Climate. The dissipation questions come up now and then in several Blogs.

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While pursing the NASA/GISS ModelE coding as part of getting back to the dissipation questions that have come up on Lucia’s Blog in this thread, I ran across yet even more interesting coding. The thread at Lucia’s is related to the posts on this Blog here, here, and here. The dissipation questions come up now and then in several Blogs.

But first, a short diversion.
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There are several discussions floating around on the subject of comparing GCM-calculated numbers with experimental data. Climate Audit and Lucia both have several threads. There are too many threads to give links; let me know if you need a specific thread. One focus of these discussions is the ensemble-average approach that is considered to be necessary for the comparisons. The ensemble is made up of the results from the various different versions of GCMs that calculate the results. Not only are GCMs different from each other, but the suggested approach is to make perturbations in the initial conditions between the runs.

I have mentioned that the results do not reflect the effects of perturbations in only the initial conditions. Everything about the approach is different between the runs. The GCMs are based on different continuous-equation models, numerical solution methods, application procedures, run-time options, and users, and maybe other aspects. How can we be sure that the results are all appropriate for Earth?

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In a previous post I gave an illustration of how GISS/NASA employees have implemented new and innovative ways to produce inactive code using the capabilities provided by F90/95. I had run across the following statements in routine DIAG.f:

EWATER(J)=EWATER(J)+EL !+W*(SHV*T(I,J,L)*PK(L,I,J)+GRAV
! * *HSCALE*LOG(P(I,J)/PMID(L,I,J)))

The ‘!’ in the first line is going to be very difficult to remember it exists and correctly maintain. Someone might come along and say, “I wonder what that’s doing in the middle of an executable statement.” and promptly un-do the comment. Or un-do the comment of the second line while overlooking the comment in the first line. That would make a screw up on several levels.

Today I have found many more examples of innovative coding by employees of GISS/NASA. It is clear that the NASA Software Quality Assurance procedures are ignored by GISS/NASA. It is equally clear that there are no Software Quality Assurance procedures being applied to the GISS/NASA ModelE code. None.

Update November 2, 2008 down near the end.

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Not my kind of Engineering.

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Well, GISS/NASA employee Dr. Gavin Schmidt has done it again. He has given direct proof that the fundamental concepts of software Verification and Validation and other Software Quality Assurance procedures are not in the work universe of GISS/NASA.

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of equation systems that do not possess chaotic response.

Executive Summary
The original PDEs that describe the Rayleigh-Benard convection problem do not posses chaotic behavior. The chaotic response observed with Lorenz-like low-order models (LOM) obtained via mode expansions disappears whenever sufficient resolution is used in the numerical solution methods applied to the original PDEs.

The low order model of the Lorenz equations omits the terms that are responsible for interaction between smaller scales and the large scales. The very interactions that form the basis for invoking the turbulence analogy.

GCMs are consistent with the chaotic response obtained from incorrect low-order models (LOM) expansions of PDEs.

GCMs are consistent with the chaotic response obtained from incorrect solutions to ODEs and PDEs.

GCMs are consistent with the chaotic response observed whenever insufficient resolution is used with numerical solution methods.

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Using the NASA/GISS ModelE code browser I ran across the MODULE CONSTANT in which several constants are setup as parameters.

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