Frequency content of sea surface height variability from internal gravity waves to mesoscale eddies

TitleFrequency content of sea surface height variability from internal gravity waves to mesoscale eddies
Publication TypeJournal Article
Year of Publication2017
AuthorsSavage A.C, Arbic B.K, Richman J.G, Shriver J.F, Alford MH, Buijsman M.C, Farrar J.T, Sharma H., Voet G., Wallcraft A.J, Zamudio L.
JournalJournal of Geophysical Research-Oceans
Volume122
Pagination2519-2538
Date Published2017/03
Type of ArticleArticle
ISBN Number2169-9275
Accession NumberWOS:000400678900047
Keywordsaccuracy; dissipation; energy; general-circulation; global ocean; ocean circulation model; satellite altimetry; spectra; tide-gauge; wind
Abstract

High horizontal-resolution (1/12: 5 degrees and 1/25 degrees) 41-layer global simulations of the HYbrid Coordinate Ocean Model (HYCOM), forced by both atmospheric fields and the astronomical tidal potential, are used to construct global maps of sea surface height (SSH) variability. The HYCOM output is separated into steric and nonsteric and into subtidal, diurnal, semidiurnal, and supertidal frequency bands. The model SSH output is compared to two data sets that offer some geographical coverage and that also cover a wide range of frequencies-a set of 351 tide gauges that measure full SSH and a set of 14 in situ vertical profilers from which steric SSH can be calculated. Three of the global maps are of interest in planning for the upcoming Surface Water and Ocean Topography (SWOT) two-dimensional swath altimeter mission: (1) maps of the total and (2) nonstationary internal tidal signal (the latter calculated after removing the stationary internal tidal signal via harmonic analysis), with an average variance of 1: 05 and 0: 43 cm(2), respectively, for the semidiurnal band, and (3) a map of the steric supertidal contributions, which are dominated by the internal gravity wave continuum, with an average variance of 0: 15 cm2. Stationary internal tides (which are predictable), nonstationary internal tides (which will be harder to predict), and nontidal internal gravity waves (which will be very difficult to predict) may all be important sources of high-frequency "noise" that could mask lower frequency phenomena in SSH measurements made by the SWOT mission.

DOI10.1002/2016jc012331
Short TitleJ Geophys Res-Oceans
Student Publication: 
No