MultiTaper Method-Singular Value Decomposition (MTM-SVD): spatial-frequency variability of the sea level in the southeastern Pacific

Marco Correa-Ramirez, Samuel Hormazabal


DOI: https://doi.org/10.3856/vol40-issue4-fulltext-19

Eighteen years of satellite data on sea level and wind stress in the southeastern Pacific region, were used to show the capabilities of Multitaper Method - Singular Value Decomposition (MTM-SVD) as a valuable method to analyze multiple time series distributed over a large area on the ocean. Here we performed a comprehensive review of the MTM-SVD method,that was first proposed by Mann & Park (1999), and also we done an implementation of the MTM-SVD algorithms in MATLAB (MAtrix LABoratory), in order to take advantage of the graphical capabilities that brings this computational language and make easier the result interpretation. The MTM-SVD allowed to obtain a regional view of the main frequencies of sea level variability, and showed the explained variance along the study area for each frequency. Besides, the method also shown the spatial oscillation patterns on each frequency, both stationary or propagation patterns. A significant annual and interannual variability appear dominate much of the sea level fluctuations in the southeastern Pacific. The annual signal was found associated with the wind stress and the propagation of a Rossby wave. The interannual signal was strongly observed associated with the El Niño and the Southern Oscillation. On these frequencies the sea level perturbations were generated on the coast, and then traveling westward at a speed close to the theoretical propagation of the first baroclinic mode of a Rossby wave.

Correa-Ramirez M, Hormazabal S. MultiTaper Method-Singular Value Decomposition (MTM-SVD): spatial-frequency variability of the sea level in the southeastern Pacific. Lat. Am. J. Aquat. Res.. 2017;40(4): 1039-1060. Available from: doi:10.3856/vol40-issue4-fulltext-19 [Accessed 11 Dec. 2019].
Correa-Ramirez, M., & Hormazabal, S. (2017). MultiTaper Method-Singular Value Decomposition (MTM-SVD): spatial-frequency variability of the sea level in the southeastern Pacific. Latin American Journal of Aquatic Research, 40(4), 1039-1060. doi:http://dx.doi.org/10.3856/vol40-issue4-fulltext-19