Changes between Version 7 and Version 8 of 2019WP/ENHANCE-05_SimonM-Harmonic_Analysis

Timestamp:

2019-08-23T19:59:26+02:00 (5 years ago)

Author:

smueller

Comment:

--

2019WP/ENHANCE-05_SimonM-Harmonic_Analysis

@@ -25 +25 @@
 Tidal harmonic analysis of model fields based on multiple linear least-squares regression is available in the current trunk version of NEMO in module `diaharm` (source:/NEMO/trunk/src/OCE/DIA/diaharm.F90@10835). It is restricted to the analysis of sea-surface height and barotropic velocity fields, to a hard-coded maximum number of time slices within uninterrupted model runs, and its memory footprint during the whole analysis period can be very large. The current implementation has aspects that are deprecated (use of a pre-processor key, non-conventional namelist variable names, and statical allocation of potentially oversized arrays) and appears to be computationally inefficient. Further, it lacks sought-after features, such as the analysis of a wider range of model fields (including three-dimensional fields) and the possibility to span the analysis time period across restarted model runs, which have become available in more efficient alternative implementations of the same analysis method by N. Bruneau (pers. comm.) and E. O'Dea (https://forge.ipsl.jussieu.fr/nemo/browser/branches/UKMO/dev_5518_tid_analysis_restart) in previous NEMO versions. In addition, the harmonic analysis diagnostics of module `diaharm` remains deactivated, and thus its compilability untested, during the standard tests of the SETTE test suite.
 
+=== Proposed replacement of the tidal harmonic-analysis diagnostics by a generic formulation for multiple linear regression analysis 
+
+Rather than adapting and upgrading an existing implementation of harmonic-analysis diagnostics (the current implementation in the trunk version or an existing alternative implementation) for the latest reference version of NEMO, the development of generic multiple linear least-squares regression analysis diagnostics for NEMO as outlined below in the form of a new module `diamlr` (source:/NEMO/trunk/src/OCE/DIA/diamlr.F90), additional XIOS configuration, and an off-line tool is proposed. This new diagnostics would readily allow for tidal harmonic analysis, and module `diaharm` (source:/NEMO/trunk/src/OCE/DIA/diaharm.F90) could be removed. In addition to tidal harmonic analysis the new development would facilitate non-tidal applications, such as the identification of the seasonal cycle or linear trends in model fields.
+
 == Tests