Models, Methods, Software

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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When the basis of the mathematical models used in AOLGCM models/codes are discussed it is almost always stated that the ‘fundamental laws of conservation and mass and energy’ are at the foundations of the models. This is an incomplete, and somewhat incorrect, statement on several levels.

Conservation of mass and energy is the focus of the following discussion.

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The recent results of an Independent Verification of a calculation at Climate Audit and discussed here brings me to mention the editorial policies of scientific journals relative to Verification, Validation, Software Quality Assurance, and Qualfications of models, methods, software, calculations, users, and applications. I have posted comments about the issues relative to publication of peer-reviewed papers on several blogs and given more detailed discussion here.

According to the results of a very unscientific survey by me, the scientific journals have no interest in these very important issues. Many engineering journals, however, have addressed the problems and developed editorial appropriate policies which must be met by authors.

A little over two years ago I wrote letters to the editors of several scientific journals in which the climate change community publishes papers. I have uploaded an example of the letter.

I think it’s time to followup on that letter, for a second time. Read the rest of this entry »

Here’s an example of what a lack on coding guidelines (or ignoring them) can lead to. From the NASA/GISS ModelE online source code browser:

SUBROUTINE SURFCE 1,30
!@sum SURFCE calculates the surface fluxes which include
!@+ sensible heat, evaporation, thermal radiation, and momentum
!@+ drag. It also calculates instantaneous surface temperature,
!@+ surface specific humidity, and surface wind components.
!@auth Nobody will claim responsibilty

This is the entire header information for a 1228-line routine.

The last line says it all.

“The purpose of computing is insight, not numbers.” Richard Hamming

In order to gain insight, deep understanding of the source of the numbers is of paramount importance. Until deep understanding of the source of the numbers is attained, the numbers do not provide insight. In my opinion, deep understanding of the source of the numbers is best attained by a bottom-up approach. Merely comparing line, contour, or 3-dimensional plots of some calculated numbers does not constitute either understanding or verification/validation.
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Here is a start on a bibliography for V&V and SQA books and articles.
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I have a kind of long discussion paper on V&V and SQA that I put together a couple of years ago. I have uploaded a copy V&V and SQA.

I have posted several short discussions of software Verification, Validation (V&V) and Software Quality Assurance (SQA) issues a few times at several blogs. I continue to hope that more complete discussions of significant software engineering issues will follow. So far that has not happened. I have made other direct contacts too, but also without success.

Documentation of the models, methods, and software is the key focus relative to V&V and SQA . My research is conducted mainly on the Web. It is entirely possible that I have missed what I’ve been looking for. But no one has yet provided the information that I know is needed in order to provide creditability to projections/predictions from any and all computer software.

All these codes, and all other aspects of all the software used in the climate-change community, belong to us. The continued lack of open documentation is an affront to all of us who have paid for these products and their applications. The climate-change community must open the documentation windows and let some sunshine in.
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