= ''ENHANCE-05_SimonM-Harmonic_Analysis''

Last edition: '''[[Wikinfo(changed_ts)]]''' by '''[[Wikinfo(changed_by)]]'''

The PI is responsible to closely follow the progress of the action, and especially to contact NEMO project manager if the delay on preview (or review) are longer than the 2 weeks expected.

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== Summary

The harmonic-analysis diagnostics available in the current reference code is limited to two-dimensional fields (surface only), is activated via a preprocessor key, uses unconventional namelist parameter names, uses a mixture of dynamic and static allocation for large arrays, and appears to be computationally inefficient. Further, while being based on multiple linear regression, the current implementation does not provide for regressions on harmonic components other than tidal constituents.

This action will replace the current tidal harmonic-analysis diagnostics with a generic implementation for multiple linear regression analysis that can be utilised for both tidal harmonic and non-tidal regression analyses. This implementation will provide harmonic-analysis diagnostics enhancements previously tested in a pre-4.0beta NEMO version by N. Bruneau: the analysis of three-dimensional fields, analysis across model restarts, and improved computational efficiency.


In contrast to both the existing harmonic analysis diagnostics in the reference NEMO code and the enhanced pre-4.0beta version by N. Bruneau, the new implementation will make extensive use of XIOS and an off-line tool. This approach should make it possible to simplify the regression analysis-related Fortran module in the core NEMO code, to relocate the regression-analysis configuration to XIOS configuration files, and to enable the selection of any model field handled by XIOS for analysis.

See ticket ''#2175''.


== Preview 

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== Tests

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== Review

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