Ocean spectral data assimilation without background error covariance matrix
| Autor: | Peter C. Chu, Tetyana Margolina, Chenwu Fan |
|---|---|
| Přispěvatelé: | Naval Postgraduate School (U.S.), Oceanography |
| Rok vydání: | 2016 |
| Předmět: |
World ocean synoptic monthly gridded data
010504 meteorology & atmospheric sciences Meteorology Gaussian Oceanography 01 natural sciences Physics::Geophysics Matrix decomposition Background error covariance matrix symbols.namesake Data assimilation Observational error covariaince matrix Optimal interpolation Physics::Atmospheric and Oceanic Physics Eigenvalues and eigenvectors 0105 earth and related environmental sciences Mathematics Observational error 010505 oceanography Covariance matrix Lagrangian operator Ocean surface topography symbols Ocean data assimilation Optimal spectral decomposition (OSD) Algorithm Basis functions Interpolation |
| Popis: | The article of record as published may be found at http://dx.doi.org/10.1007/s10236-016-0971-x Predetermination of background error covariance matrix B is challenging in existing ocean data assimilation schemes such as the optimal interpolation (OI). An optimal spectral decomposition (OSD) has been developed to overcome such difficulty without using the B matrix. The basis functions are eigenvectors of the horizontal Laplacian operator, pre-calculated on the base of ocean topography, and independent on any observational data and background fields. Minimization of analysis error variance is achieved by optimal selection of the spectral coefficients. Optimal mode truncation is dependent on the observational data and observational error variance and determined using the steep-descending method. Analytical 2D fields of large and small mesoscale eddies with white Gaussian noises inside a domain with four rigid and curved boundaries are used to demonstrate the capability of the OSD method. The overall error reduction using the OSD is evident in comparison to the OI scheme. Synoptic monthly gridded world ocean temperature, salinity, and absolute geostrophic velocity datasets produced with the OSD method and quality controlled by the NOAA National Centers for Environmental Information (NCEI) are also presented. Office of Naval Research Naval Oceanographic Office Naval Postgraduate School |
| Databáze: | OpenAIRE |
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